Opinion by

The Carothers Contracting Company entered into an agreement with the City of Altoona for the construction of a large reservoir, and the National Surety Company, of New York, became surety for the contract. Various parts of the work were separately set out, but the plans and specifications, as a whole, called for a completed reservoir. As the separate parts relate to the question now before the court, provision was made for a core-wall to be built on solid foundation; against this core-wall, on the inner and outer sides, embankments were to be placed, and on the inner embankment a top covering of riprap and stone facing. The details were clearly set forth. In the progress of the work, certain excavation was necessary; that is, earth was to be removed to secure proper foundation for the core-wall, depth for the pipe-trenches leading from the reservoir and elsewhere, and for the embankments. In making the excavations, all rock encountered was to be taken out; boulders over a certain size and strata formation were to be blasted. Approximately 500,000 cubic yards of earth were moved from the borrow pits, inside the flow-lines of the reservoir, to the embankment. All rock blasted under these *195circumstances was to be paid for at a unit price of $2 per yard. It was, however, expected there would be enough loose stone from the borrow pits and other excavations to make the facing and the riprap for the inner slope of the embankment next to the core-wall: compensation for this was fixed at thirty cents per yard, as embankment. It was constructed as follows: When the earth, placed against the core-wall on the inside, reached a specified slope, it was protected by a covering of rock at least four feet deep from the bottom to an elevation where the slope-paving began, and from thence a two-foot backing was required. There was not sufficient loose stone from the various excavations to finish the work of riprap and facing. The contractor at no time denied its obligation to provide the material for this work. It was necessary to go outside the flow-lines to get it, at an additional expense, by blasting the rock from the hillside. The contractor claimed it should be paid rock price for this work. The city authorities admitted the error as to amount of loose stone on hand from the excavations, but held it was an uncertainty arising in the progress of the work, which was taken care of by the extra work clause, which reads as follows: “It is understood that extra work or extra material, as considered in the contract and specifications, is work or material that the contractor is required to perform or furnish, and for which no definite price per unit is fixed in the contract, specifications or proposals^” The city authorities, by letter of October 8th, directed the stone be procured at a designated point outside the flow-lines, the contractor to be paid the extra work price, viz: cost plus fifteen per cent for profit, superintendency and general expense for “quarrying and loading the stone,” the city paying, in addition, the contract price of thirty cents per yard when it was in place in the embankment. The contractor declined to accept this determination and in reply set up an entirely new price not mentioned in the agreement, namely, force account, with a per diem charge *196for engine, cars and track. It refused to depart from this price during the period of discussion, ending November 12th, when it refused to do the work, the city suspending the contract December 7th. The municipality served notice of suspension on the surety; this company, under the surety agreement, proceeded to complete the work as if no default or abandonment had occurred. The contractor sued in its own behalf and for the benefit of the use-plaintiffs, to whom part of its claim had been assigned, seeking to recover the amount of the last estimate due when a default was declared, the retained percentage and damage for an unlawful rescission of the contract. A judgment was directed against the plaintiffs ; hence this appeal.

It is urged that under the contract the quarrying of stone for the slope-facing and riprap was to be paid for as rock excavation. We have endeavored to point out generally the different parts of the work, how they fitted into each other, and were so specified that they could have been let to different contractors. By the express terms of the contract, as well as the general scheme of the work, rock excavation was limited to such work as was necessary in the construction of the reservoir, that is, such excavation as was actually demanded at the places indicated on the plans. The core-wall must have an even rock foundation of a sufficient depth, in this case from ten to twenty feet. Loose rock within that space must be taken away, otherwise the foundation would be insecure. The same may be said of the pipe-trenches. The earth within the flow-lines was to be used for the embankments, securing greater storage capacity, as well as evening up the flow-lines of the reservoir. It was at these places loose rock was expected to be found in quantities sufficient to cover the inner slope when the work was completed. There were no uncertainties about the work to be done; the only facts made doubtful as the work progressed were, the place where the balance of the loose rock was to be secured, and the price the contractor *197was to be paid. The specifications were explicit in declaring a sufficient quantity of rock would be taken from the various excavations. This having failed, it had to be secured at a place different from that mentioned in the agreement. Sufficient might have been gotten from the hillside, at a distance, or the way the city directed, but it is clear the quarrying and loading of the stone must necessarily be work and material that the contractor was required to furnish, for which no definite price per unit was fixed, and covered by the extra work clause of the contract. The contractor, therefore, could not decline to proceed with the work; nor was the fact that the appellee rescinded the contract while the discussion was going on, material. The stipulated price for extra work or material mentioned in the contract refers to a gross sum or certain figure; it does not affect the determination of the question.

The doctrine of substantial performance has no place here as the reservoir was not in any sense completed until the facing and riprap were in place; a small part of the reservoir might be used, but not until that work was done: Gillespie Tool Co. v. Wilson et al., 123 Pa. 19, 26; Denahan & Co. v. Holmesburg Granite Co., 45 Pa. Superior Ct. 399, 403. The appellants had been paid for everything due until the last estimate; this, under the contract with the surety company, was to be paid the latter company.

When the city waived its option to rescind or annul the contract because it was not completed within the time limited, it did not thereby deprive itself of the future right to annul or suspend the contract for work done in an unsatisfactory manner, or when the contractor refused to do certain parts of the work required by the agreement; the city was not estopped from declaring a forfeiture, annulment, or suspension for sufficient cause other than the time of completion: Wiggin v. Marsh Lumber Co., 77 W. Va. 7, 16; Beltinck v. Tacoma *198Theatre Co. et al., 61 Wash. 132, 136; Nibbe v. Brauhn, 24 Ill. 268, 270.

When the contract was annulled, the last monthly estimate of $4,816.60 was due appellants, and $10,000 was retained by the city as an indemnity against loss through anything arising out of the contract. The terms of the suretyship provided: “If the said principal shall in any manner default in the performance of any matter or thing in said contract......the surety company shall have the right, at its option, to assume......said contract and to proceed thereunder as if no default or abandonment had occurred......and all moneys agreed therein to be paid said principal and which at the time of the default [shall] be due the principal shall thereupon become payable to the company and shall be paid to it; anything to the contrary notwithstanding.” The city properly paid the surety company the amount of the last monthly estimate; and, when the final estimate was given, the retained $10,000 was to be paid. But appellants urge that the surety company has not collected, and may never collect the retained percentage. The fact none the less remains that the retained percentage, by the terms of the suretyship, is assigned to the surety company, which is in duty bound to collect it, less any claim the city may have thereagainst, and a failure so to do after proper notice will make it, and perhaps the city also, liable to an accounting for the net balance due by the city, as well as any balance due on the last estimate paid to the surety company. Upon this record, however, the matter is not ripe for determination and we shall, therefore, protect appellants’ rights by the judgment we enter.

After careful consideration of all the assignments of error, they are dismissed, and the judgment of the court below is affirmed, without prejudice to the right of the appellants to proceed for the moneys herein indicated by such action in law or equity as shall be warranted by the facts.