The demandants in the first of these actions and the tenants in the second, though differently named, are by amendment the same parties, and the cases have been heard together.
The parties claim title to the premises under grants from the Commonwealth. The Winnisimmet Company owned a lot on the shore, which extended to low water mark. It was bounded by straight lines which are nearly or quite parallel, and on the northwesterly side it adjoined the land of Isaac Harris, and on the southeasterly side the land of Samuel Aspinwall, whose title afterwards passed to Wyman and others. By St. 1837, c. 191, the legislature granted to Harris authority to extend his wharves straight into the channel, as far as the line which had been established by the commissioners appointed under the resolve of 1835 for the survey of Boston Harbor. By St. 1837, c. 211, passed the same day, the Winnisimmet Company were authorized to extend their wharves to the commissioners’ line ; and by c. 212, passed the same day, Aspinwall was authorized to extend his wharf to the same line. By the terms of the grant to Harris, his southeasterly line, adjoining the Winnisimmet Company, was to be straight. It is also to be presumed that the southeasterly line of the Winnisimmet Company, adjoining Aspinwall, was to be extended to the commissioners’ line without deflection, unless some fact appears to show a contrary intention.
One fact which is relied on to show such contrary intention is, that the north end of Boston, including the estates of both the parties to these actions, was a headland ; and on a headland where the shore is convex the curvature makes it often necessary *438to deflect the boundary lines as they extend outwards into the sea, in order to make a proper division between adjoining lota thus extended. But the shore of a headland seldom curves with any uniformity. In some parts there may be a straight shore, and in others there may be coves and creeks upon which several conterminous lots are bounded, and therefore no uniform rule can be laid down. Deerfield v. Arms, 17 Pick. 45. Walker v. Boston & Maine Railroad, 3 Cush. 1. It does not appear that the lot of the Winnisimmet Company was situated on a convex shore; and from the mere fact that it was situated on a large headland, which included many lots, we cannot say that the easterly line should be produced otherwise than as a straight line to its outer boundary at the commissioners’ line.
But the company rely upon another fact. Nathaniel Goddard owned the lot next southeasterly of Aspinwall, and by St. 183.9, c. 95, the legislature granted to him the right “to extend his wharves to the commissioners’ line,” bounding him on the northerly side by a line drawn in continuation of the line between him and Aspinwall, and on the southeasterly side by a line drawn in continuation of the boundary line between him and Joseph W. Revere. The lots of Aspinwall and Goddard were both considerably wider at low water mark than at the opposite end, and of course they would continue to widen by the extension of their lines without deflection to the commissioners’ line. The lot of Goddard is very much wider at the commissioners’ line than at the opposite end, and by a subsequent indenture he and Aspinwall established the line between themselves. By this line the lot of Aspinwall continues to grow wider as it approaches the commissioners’ line. But neither the grant to Goddard nor the subsequent establishment of the line between him and Aspinwall can affect the construction of the grant to the Winnifimmet Company. In Goddard’s grant the legislature defined his boundaries, and he and Aspinwall had a right to establish the line between them arbitrarily, as they might think proper.
At this late day it would probably be impossible to ascertain the exact position of the original shore at the place in controversy, Neither party has attempted to do-it in this case. Foi *439this reason it is useful to know what the Winnisimmet Company and Aspinwall did in respect to the establishment of the extended line between them, and the occupation of their respective. lots, soon after the grants were made, for they must be presumed to have known the facts and their own legal rights at that time. Such evidence is held to be admissible, and to be entitled to great weight in construing the grants. Sparhawk v. Bullard, 1 Met. 95. Stone v. Clark, Ib. 378. Jennison v. Walker, 11 Gray, 423, 427.
It appears that they established a line produced without deflection, drove piles upon it, and occupied accordingly. The Winnisimmet Company are not estopped to show that they made, a mistake in assenting to this line, but they offer no evidence tending to show such mistake. We do not see, upon all these facts, any ground for interpreting the grant to the company so as to require a deflection of their line, in order that their lot may be widened at its outward end.
Judgment must be for the tenants in the first action, and for the demandant in the second action.