In the Report on the Invertebrate Animals, this singular fact is recorded, which teaches us to put a new value on time and space. “The distribution of the marine shells is well worthy of notice as a geological fact. Cape Cod, the right arm of the Commonwealth, reaches out into the ocean, some fifty or sixty miles. It is nowhere many miles wide; but this narrow point of land has hitherto proved a barrier to the migrations of many species of Mollusca. Several genera and numerous species, which are separated by the intervention of only a few miles of land, are effectually prevented from mingling by the Cape, and do not pass from one side to the other…. Of the one hundred and ninety-seven marine species, eighty-three do not pass to the south shore, and fifty are not found on the north shore of the Cape.” That common muscle, the _Unio complanalus_, or more properly _fluviatilis_, left in the spring by the musk-rat upon rocks and stumps, appears to have been an important article of food with the Indians. In one place, where they are said to have feasted, they are found in large quantities, at an elevation of thirty feet above the river, filling the soil to the depth of a foot, and mingled with ashes and Indian remains. The works we have placed at the head of our chapter, with as much license, as the preacher selects his text, are such as imply more labor than enthusiasm. The State wanted complete catalogues of its natural riches, with such additional facts merely as would be directly useful. The reports on Fishes, Reptiles, Insects, and Invertebrate Animals, however, indicate labor and research, and have a value independent of the object of the legislature. Those on Herbaceous Plants and Birds cannot be of much value, as long as Bigelow and Nuttall are accessible. They serve but to indicate, with more or less exactness, what species are found in the State. We detect several errors ourselves, and a more practised eye would no doubt expand the list. The Quadrupeds deserved a more final and instructive report than they have obtained.