FACTS AND OBSERVATIONS. 



other countries. They make seventeen appearances in Great Britain, six in France, five in Russia, 

 and four in North America, several other appearances being scattered singly here and there. 



The very beautiful genus Actinoceras is widely distributed; it is in eleven great American 

 districts, and in seven European. 



Cyrtoceras is in twenty-two countries. Speaking of Europe and North America, it is in eleven 

 each. In Bohemia it is surprisingly numerous. 



The Discosurus of Lake Huron, the State of New York, and Prince Rupert's Land is exclu- 

 sively American. It is remarkable for the flat, nummulite-like form of its septa, and their very 

 rapid diminution in size. 



The seventeen species of Goniatites only exist in Bohemia. None of them are in passage- 

 beds ; live of them are in fauna F, the others are in G. 



The genus Lituites is seen in twenty-three countries, thirteen being European. 



A Nautilus (sp. involvens) has a singularly wide dispersion. It is found in Niti of the 

 Himalayas (India), in the valleys of the Mississippi and the St. Lawrence, in Newfoundland, 

 Bohemia, Russia. 



The Orthoceratites are found in thirty-nine great countries, in 708 species, 304 of these being 

 in the little area of Bohemia, a circumstance most extraordinary, but perhaps being partly capable 

 of explanation by the probable increase there of the plutonic heat at the time, as well as by the 

 favourable nature of the sediments. 



The simplest form in this order is that of Piloceras, S alter ; and it is found associated with the 

 genera Cyrtoceras, Lituites, Nautilus, Orthoceras in Newfoundland, the Mingan Isles (G. St. Law- 

 rence), and Canada. It also forms part of the Primordial community, composed of American 

 species, settled on the north-west extremity of Scotland. 



That there should be in these Primordial times animals of such a high rank as these, suggests, 

 with no small urgency, the probability of their being the remains of a large and lost fauna. 



The abundance of these large and voracious sea-creatures implies an abundance of prey, a sea 

 full of life, now out of our observation. 



They are usually found buried in many deposits. Of this a tolerably accurate idea may be 

 formed from the following Table, made out from Quart. Journ. Geol. Soc. Lond. xv. p. 334. It 

 may be allowed to speak for other countries, as well as for other Orthoceratites, besides those 

 already inserted. 



TABLE II. The sediments in which seven British genera are found. 



Being free swimmers, and changing their quarters according to seasons and certain instincts, 

 these mollusks fall into many bottoms. The mixed deposits usual in medial depths hold the 

 greater part of these remains. Seventy-three species are in calcareous sediments, and thirty-four 

 in non-calcareous. This list was drawn up under the inspection of Mr. J. "\V, Salter, 



