18 History of Hingham. 



ized forms of life that have left impressions, the characters of 

 which can be deciphered. All that can be known of the early 

 species, therefore, vegetable or animal, must apparently be learned 

 from what has been, or may yet be discovered in them. The 

 estimated duration of this period, taking Thomson's basis as 

 shown, by the table, is nearly 3,000,000 years. The forms of life 

 preserved by the strata are all of course marine, and consist 

 largely of impressions of Trilobites, — animals that lived in the 

 shallow waters of the coasts, upon the muddy and sandy surfaces 

 below, and finally became entombed in their substance. There 

 were many species of these animals in these and later formations, 

 but they all became extinct before the close of the Carboniferous 

 Period. The fortunate discovery by Prof. Wm. B. Rogers of the 

 remains of some of these in the slate rocks of Braintree, furnished 

 proof that a part at least of the slate of the Boston Basin belongs 

 to the Primordial Period. 



We will now pass over the immense time in the history of the 

 earth, numbering many millions of years, during which other rocks 

 of the Silurian and of the Devonian Ages were deposited beneath 

 the sea to the enormous thickness of one hundred thousand feet, 

 all abounding in forms of life, as scarcely more than a mention 

 can be made of any period that has not left mementos of its pas- 

 sage over or about this particular territory. 



Carboniferous Age. — Of the Carboniferous Age, it may be said 

 that notwithstanding the contrary views hitherto held by geologists, 

 it is yet by no means settled that the Conglomerates and Associated 

 rocks of Hingham are not formations of this age rather than of 

 the Primordial Period of the Silurian Age. However this may 

 be, it is certain that a considerable portion of the rock formations 

 near and south of Hingham, bordering Rhode Island and extend- 

 ing into that State, is made up of the deposits of the Carboniferous 

 Age, embracing not only Conglomerates of like character as those 

 of the Boston Basin, but also large beds of Anthracite with the 

 accompanying shales and fossil plants, demonstrating them to be 

 contemporaneous with those of the great coal-fields of Pennsyl- 

 vania and other regions of the continent. This fact suggests, 

 what it is well to bear in mind, that the temperature of the region 

 we inhabit, as well as that of the whole North, was then very 

 much warmer than in succeeding ages, sufficiently so to allow 

 the growth of tropical plants of which coal itself is a product, not 

 only in the Alleghany and the western coal regions, but in those 

 of Massachusetts, of Cape Breton, and of the Arctic Circle. It is 

 certainly a striking fact that upon the surface of this town, 

 where in after ages rested for thousands of years ice of great 

 thickness, flourished tree-ferns, and other plants of forms now 

 found only in the torrid zone ; but there can be no question 

 that this was the case. The rock formations of the Carbon- 

 iferous Age measure in thickness about 22,000 feet, and the esti- 

 mated time for their deposit on Thomson's basis is about 4,000,000 



