The Hudson and the Mohawk constituted the area of the Old West in this part of the eighteenth century. With them were associated the Wallkill, tributary to the Hudson, and Cherry Valley near the Mohawk, along the sources of the Susquehanna. The Berkshires walled the Hudson in to the east; the Adirondacks and the Catskills to the west. Where the Mohawk Valley penetrated between the mountainous areas, the Iroquois Indians were too formidable for advance on such a slender line. Nothing but dense settlement along the narrow strip of the Hudson, if even that, could have furnished the necessary momentum for overcoming the Indian barrier; and this pressure was lacking, for the population was comparatively sparse in contrast with the task to be performed. What most needs discussion in the case of New York, therefore, is not the history of expansion as in other sections, but the absence of expansive power. The fur-trade had led the way up the Hudson, and made beginnings of settlements at strategic points near the confluence of the Mohawk. But the fur-trader was not followed by a tide of pioneers. One of the most important factors in restraining density of population in New York, in retarding the settlement of its frontier, and in determining the conditions there, was the land system of that colony. From the time of the patroon grants along the lower Hudson, great estates had been the common form of land tenure. Rensselaerswyck reached at one time over seven hundred thousand acres. These great patroon estates were confirmed by the English governors, who in their turn followed a similar policy. By 1732 two and one-half million acres were engrossed in manorial grants.[80:1] In 1764, Governor Colden wrote[80:2] that three of the extravagant grants contain, as the proprietors claim, above a million acres each, several others above 200,000. * * * Although these grants contain a great part of the province, they are made in trifling acknowledgements. The far greater part of them still remain uncultivated, without any benefit to the community, and are likewise a discouragement to the settling and improving the lands in the neighborhood of them, for from the uncertainty of their boundaries, the patentees of these great tracts are daily enlarging their pretensions, and by tedious and most expensive law suits, distress and ruin poor families who have taken out grants near them. He adds that "the proprietors of the great tracts are not only freed from the quit-rents, which the other landholders in the province pay, but by their influence in the assembly are freed from every other public tax on their lands."