The Geology of Hingham. 



13 



Formations. 



MESOZOIC TIME 

 Reptilian Age. 

 Triassic Period. 



Jurassic Period. 



Cretaceous Period, 



ancient types of cockroach- 

 es, walking-sticks, May-flies, 

 etc. 



< )ther extinct Orders are 

 also represented. 



Plants : 



Cycads and new forms 



of Ferns, Equiseta, 



Conifers. 

 No species yet met. ivith 



of Grass or Muss. 

 No Palms. 



No Angiosperms, the 

 class which includes all 

 our New-England plants 

 having a bark, excepting 

 Conifers, as maples, wil- 

 lows, birches, oaks, etc. 

 Animals : 



Vertebrates in great 

 numbers and of great 

 size. Fishes, Reptiles, 

 perhaps Birds. 

 First appearance of 



Mammals. 



Plants : 



Similar to those of the 

 Triassic Period. 

 Animals : 

 Gigantic Reptiles, among 



them flying lizards. 

 Marsupial mammals. 

 First appearance of os- 

 seous jishes. 

 Birds. 



Plants : 



First appearance of the 



Angiosperms. 

 Of the Angiosperms, 



oaks, beeches, poplars, 



willows, hickories, and 



others existed. 

 First appearance of 



Palms. 

 Animals : 



Reptiles were very nu- 

 merous and of great size, 

 one genus of which, 

 Mosasaurus, had species 

 varying from forty-five 

 to eighty feet in length, 

 and having been snake- 

 like in form, may well 

 be termed, as by Dana, 

 sea-serpents of the era. 



General Remarks. 



In the deposits of the Pe- 

 riods of the Reptilian Age, 

 first appear insects of the 



to preat changes along the coast 

 of New England, in New Bruns- 

 wick, Nova Scotia, and generally 

 over all the surface east of the 

 Mississippi. 



The forests of this period differed 

 much from those of the Carbon- 

 iferous in having neither Sigil- 

 larids nor Lepidodendrids. Tree- 

 ferns, Conifers, and Cycads were 

 the prevailing forms. 



There were great disturbances of 

 the surface during the Triassic 

 Period, as shown by the vast 

 ridges of trap rocks which were 

 forced up through the strata in 

 a molten condition, and now form 

 some of the prominent elevations 

 of tiie eastern part of the conti- 

 nent, as Mounts Tom and Holy- 

 oke of Mass., the high hills near 

 New Haven, Conn., the Palisades 

 of the Hudson, etc. 



The Jurassic Beds of Europe em- 

 brace those of three epochs, — - 

 the Liassic, Oolitic, and Weilden. 



The first of these have yielded 

 some of the best preserved and 

 finest fossils that are to be found 

 in our collections. 



Cretaceous rocks are common over 

 a considerable portion of Europe, 

 in the southeastern and southern 

 parts of the United States, and 

 in the Rocky Mountains. The 

 well-known chalk composes great 

 beds in England, and is found in 

 France and other parts of Europe. 



Great changes of level seem to have 

 taken place towards the close of 

 this period, leading to increased 

 height of the land in' the northern 

 regions, causing much change in 



