At issue are the plaintiffs’ claims of rights to use a beach in Hingham Harbor, situated behind the defendants’ homes. In a thorough and detailed memorandum of decision, a judge of the Land Court concluded that the claim of deeded rights by certain of the plaintiffs was invalid, but that some of those plaintiffs, as well as others who asserted no claim of deeded rights, nonetheless had acquired prescriptive rights to the beach, together with rights to pass over a way to gain access to the beach. We conclude that the judge erred in his conclusion that a 1929 instrument, purporting to convey rights of access to, and use of, the beach, was invalid because the grantor previously had divested all of its interest in the beach (and access ways) by operation of law. We accordingly reverse the judgment insofar as it declared that the plaintiffs claiming deeded rights do not hold the right to use the way. Because the parties to this action do not include the holder of the record interest in the beach, we vacate the judgment insofar as it adjudicated rights in the beach itself.

Background. The plaintiffs and defendants own various parcels of land in Hingham in the vicinity of Crow Point, on Hingham Harbor. The location and approximate configuration of the defendants’ properties, the beach, and the ways providing access to the beach are shown on the plan appended to this opinion. The O’Connell, Vanzura, and Schwartz properties are situated on the southwesterly side of Melville Walk as it leads from Downer Avenue to the water. The Donahue property is situated on the northeasterly side of Melville Walk, directly opposite the O’Connell property (and opposite a portion of the Vanzura property). The southern comer of the Donahue property is on the northern comer of the intersection of Melville Walk and Alice Walk.3 The beach at issue in the case is on the seaward (southeasterly) side of Alice Walk, across from the Donahue property, and on the northeasterly side of Melville Walk, across from the Vanzura property. The judge considered the land on the seaward side of Alice Walk to consist entirely of tidelands, *751and neither party challenges his finding; we accordingly will occasionally use the term “tidelands” to refer to the beach.4

In the latter part of the nineteenth century, all of the land now owned by the defendants was held by Samuel Downer. Downer died in 1881. The defendants all trace title to their respective properties to deeds out of Downer’s estate. The Vanzura property traces its title to two deeds, one dated May 4, 1897, and another dated January 11, 1917; both describe the property conveyed as bounded “on Melville Walk.” The Donahue property traces its title to a deed dated May 5, 1897, which described the property as bounded southwesterly “on Melville Walk” and southeasterly “on Alice Walk.” The O’Connell property traces its title to two deeds, both dated May 24, 1898, and both describing the property as bounded easterly “by Melville Walk.” The Schwartz property traces its title to a deed dated June 19, 1914; it described the property as bounded northeasterly “on Alice Walk.” Melville Walk and Alice Walk both are shown on recorded plans referenced in the above-described deeds; both lead from Downer Avenue, a public way, to a sandy beach abutting Hingham Harbor.

The plaintiffs claim the right to use the beach, and the right to use Melville Walk to gain access to the beach. Twelve of the twenty-four plaintiffs claim rights under an instmment executed by the trustee under the will of Samuel Downer, dated May 14, 1929,5 which conveyed:

“as appurtenant to the land on Downer Avenue and Jarvis Avenue in that part of said Hingham called Crow Point. . . the right, so far as I have power to grant the same, to use the beach and shore of Hingham Harbor opposite the end of *752Melville Walk and Lot 1 on [a certain recorded plan] for bathing, boating, and all proper forms of recreation.”

The remaining twelve plaintiffs claim rights based on prescriptive use of the beach and Melville Walk.

The evidence at trial included testimony and documentary evidence of widespread use of the beach by residents of the Crow Point neighborhood over the span of many years. An unincorporated association known as the Crow Point Community Club (club) held social events at the beach, collected dues, and maintained liability insurance. A community bulletin board was erected on the beach in the 1950’s, and a float in Hingham Harbor lay directly off the beach in the 1960’s. Boats were stored at, and launched from, the beach. In 1999, the club sent a letter to the Donahues, expressing concern that the Donahues had begun to interfere with their rights to use the beach. On May 6, 2004, the Donahues, the Stimsons (the predecessors of the Vanzuras), and O’Connell erected a locked gate across Melville Walk at its intersection with Downer Avenue, precipitating the present action.

In concluding that the 1929 Downer conveyance was invalid, the judge interpreted the Colonial Ordinance of 1641-16476 to preclude the tidelands situated on the seaward side of Alice Walk from being held separately from abutting uplands. The judge reasoned that, by 1929, the Downer estate no longer held any rights in either Alice Walk or Melville Walk because it previously had conveyed the Donahue property under the above-described 1897 deed, which described it as bounded “on” Melville Walk and “on” Alice Walk,7 and that, under the derelict *753fee statute, G. L. c. 183, § 58,8 a grant of land bounded by a way necessarily includes the fee in the entirety of the way in circumstances where the grantor owns no land on the opposite side of the way. The judge similarly concluded that, by virtue of the Colonial Ordinance, the 1897 deed operated to convey the tidelands on the seaward side of Alice Walk as well. Accordingly, because by 1929 the Downer estate previously had conveyed all of its interest in both the ways and the tidelands on their seaward side, the judge concluded that it retained nothing to convey under the 1929 instrument. The judge found, however, that eleven of the plaintiffs (including six of those claiming deeded rights)9 had made sufficient use of the beach (and of Melville Walk as their means of access) for a period in excess of twenty years to have acquired prescriptive rights.

Discussion, a. Deeded rights. “The Colonial Ordinance of 1641-1647 established that a person holding land adjacent to the sea shall hold title to the land out to the low water mark or

100 rods (1,650 feet), whichever is less.” Pazolt v. Director of the Div. of Marine Fisheries, 417 Mass. 565, 570 (1994).10 In *754his reliance on the Colonial Ordinance for the conclusion that a landowner cannot own tidelands without ownership of abutting uplands, the judge appears to have applied a rale of construction that has developed from the Colonial Ordinance: in construing deeds of land adjacent to the sea, “[t]he ‘presumption of law is, that title to the flats follows that of the upland on which they lie, and proof of title to the upland established a title to the flats.’ . . . ‘[A]n owner may separate his upland from his flats, by alienating the one, without the other.’ ” Id. at 570. See Hough-ton v. Johnson, 71 Mass. App. Ct. 825, 829 (2008).

However, as the quoted language makes clear, the principle is not absolute, and it is possible to sever tidelands from abutting uplands. Perhaps more to the point, the tidelands at issue in the present case are not adjacent to the uplands conveyed under the deed in the ordinary sense, as the uplands abut a way on one side, and the tidelands abut the way on the other. In such circumstances, the way is considered a bounding monument, and “[a] boundary ‘by a way’ . . . excludes the flats beyond.” Commonwealth v. Roxbury, 9 Gray 451, note at 524-525 (1857).11 In addition, since the 1897 deed of the Donahue property did not convey the tidelands on the seaward side of Alice Walk, the estate of Samuel Downer still owned other land on the opposite side of that way, and the derelict fee statute accordingly operates only to convey the fee in that way to its center line along the boundary of the Donahue property. In other words, contrary to the conclusion of the judge, following the 1897 deed of the *755Donahue property, the Downer estate still retained ownership of the beach, together with the fee to the center line of that portion of Alice Walk abutting the Donahue property.12

Moreover, though by 1929 the estate of Samuel Downer had conveyed all of the land it owned on both sides of Melville Walk, those conveyances operated only to divest the estate of its interest in the fee in Melville Walk, and thereby to sever the beach parcel from the land, previously held in common ownership, which furnished access to the beach. In such circumstances, the severance of title may give rise to an easement by implication or necessity over the way, even though the underlying fee has passed by operation of the derelict fee statute. See Adams v. Planning Bd. of Westwood, 64 Mass. App. Ct. 383, 390 (2005). In the absence of an express reservation, an easement by necessity will arise “only if clearly so intended by the parties to the deed.” Boudreau v. Coleman, 29 Mass. App. Ct. 621, 628 (1990), quoting from Scagel v. Jones, 355 Mass. 208, 211 (1969). The burden of proving such intent lies with the party claiming the easement, here the plaintiffs. See id. at 629, and cases cited. In part because the grantor of a deed has the ability to control its terms, the burden of proving intent is higher for a party claiming an easement by implied reservation than for a party claiming an easement by implied grant. See ibid.

In the present case, no strict necessity would require imposition of an easement over Melville Walk for access to the beach; the estate of Samuel Downer did not convey its interest in the fee of Alice Walk adjacent to lots 3-7 until 1920, by which time the fee in the entire length of Melville Walk had already passed with conveyances of the abutting parcels.13 However, the requisite *756necessity “is not an absolute physical necessity, but no more than a reasonable necessity.” Mt. Holyoke Realty Corp. v. Holyoke Realty Corp., 284 Mass. 100, 105 (1933). Moreover, evidence of use of a way for access preceding severance of the dominant parcel from the servient way will support the creation of an easement by implication. See Boudreau v. Coleman, supra at 630. Rejecting the plaintiffs’ claim of an easement by implication over Melville Walk, the judge expressly found that “[i]t is likely that Downer and the Downer Estate would have used Melville Walk as access to the Beach (in fact, it appears that the only purpose of Melville Walk in the 1897 plan, other than as access to Defendants’ lots, was as access to the Beach, since it does not lead anywhere else).”14 That finding is corroborated by the evidence in the record showing that, until 1924 (when it conveyed the large tract from which the plaintiffs’ properties later were divided), the Downer estate owned a large tract of land directly across Downer Avenue, and to the northwest of its intersection with Melville Walk. Though the Downer estate retained ownership of Alice Walk at the time of its 1897 conveyance of the Donahue property, it is extremely unlikely that it would have intended to travel to the beach solely by going northeasterly along Downer Avenue, past Melville Walk, continuing to Alice Walk, and then retreating southeasterly along Alice Walk to the beach.15 It is also of some (though not conclusive) significance *757that the destination of any travel over Melville Walk is a beach; as the judge observed, it is extremely likely that Downer, and those claiming through his estate, would have used Melville Walk for access to the beach. See, e.g, Sheftel v. Lebel, 44 Mass. App. Ct. 175, 175-176 (1998); Murphy v. Olsen, 63 Mass. App. Ct. 417, 422-423 (2005).

Contrary to the conclusion of the judge, the 1897 conveyance of the Donahue property under a deed description bounded “on” Melville Walk and Alice Walk did not operate to divest the estate of Samuel Downer of its fee interest in the beach and tidelands on the seaward side of those ways, its fee interest to the portion of Alice Walk southeast of its centerline, or its right to use Melville Walk as a means of access to the beach and tidelands. Accordingly, at the time of its 1929 conveyance of rights to use the beach and the ways, the estate of Samuel Downer held the rights it purported to convey by that instrument.16

b. Prescriptive rights. The judge concluded that some of the parties claiming deeded rights had established prescriptive rights, while others had not. However, our conclusion that the 1929 instrument validly conveyed rights to use the beach and ways compels the conclusion that none of the plaintiffs with deeded rights may sustain a claim of prescriptive use, since their use was authorized under the 1929 instrument. See generally Ivons-Nispel, Inc. v. Lowe, 347 Mass. 760, 763 (1964), quoting from Flynn v. Korsack, 343 Mass. 15, 18 (1961) (“[Wjherever there has been the use of an easement for twenty years unexplained, it will be presumed to be under claim of right and adverse, and will be sufficient to establish title by prescription . . . unless controlled or explained”). See also, e.g., Lincoln v. Emerson, 108 Mass. 87, 91 (1871) (mortgagor’s possession of property under *758equity of redemption is not adverse to mortgagee, absent dissei-sin); Foster v. Lee, 271 Mass. 200, 207 (1930) (tenant’s possession is not adverse to landlord). Moreover, our conclusion that the estate of Samuel Downer retained its interest in the tidelands on the seaward side of Alice Walk following the 1897 deed requires that we vacate so much of the judgment as declared prescriptive rights to use the beach; neither the estate (nor anyone appearing to stand as its successor in interest) is a party to this action.17

We briefly consider the defendants’ cross-appeal challenging the judge’s conclusion that five plaintiffs without any claim of right under the 1929 instrument established prescriptive rights over Melville Walk.18

Contrary to the defendants’ assertions, the evidence amply supported the judge’s conclusion that the prescriptive plaintiffs established sufficiently adverse, continuous, and defined use to support a claim of prescriptive rights over Melville Walk. The judge found (with ample record support) that each of the prescriptive plaintiffs made regular, seasonal use of Melville Walk *759for access to the beach, for periods well in excess of the required prescriptive period.19’20

Conclusion. The judgment is reversed insofar as it declares that the Donahues own the fee interest in the beach, that the 1929 deed conveyed no rights in the beach or Melville Walk to the deeded rights plaintiffs,21 that the deeded rights plaintiffs hold no easement rights in Melville Walk, and that certain of the deeded rights plaintiffs have acquired prescriptive rights to use Melville Walk and the beach. The case is remanded to the Land Court for the determination of the rights held by the deeded rights plaintiffs. The judgment is affirmed insofar as it declares that the prescriptive rights plaintiffs have established prescriptive rights in the southerly portion of Melville Walk.22 The judgment is also affirmed insofar as it dismisses the claims of the remaining plaintiffs.

So ordered.

*760Appendix.

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