DISTRIBUTION 385 



described from there 97 species of 48 genera, representing 12 

 families or higher groups, 10 of which are regarded as extinct; 

 without including many hundred specimens of cockroaches 

 which he found but did not study. In this country, many 

 species have been found in the coal fields of Illinois, Nova 

 Scotia, Rhode Island, Pennsylvania and Ohio. 



Many fine fossils of the Jurassic period have been found in 

 the lithographic limestones of Bavaria; 143 species from the 

 Lias four fifths of them beetles were studied by Heer. 



The Tertiary period has furnished the majority of fossil 

 specimens. To the Oligocene belong the amber insects, of 

 which 900 species are known from Baltic amber alone, and to 

 the same epoch are ascribed the deposits of Florissant and 

 White River in Colorado and of Green River, Wyoming. 

 These localities the richest in the world have been made 

 famous by the monumental works of Scudder. At Florissant 

 there is an extinct lake, in the bed of 

 which, entombed in shales derived 

 from volcanic sand and ash, the re- 

 mains of insects are found in aston- 

 ishing profusion. For Miocene 



forms, Of Which I,SSO European SOe- P^oblattina douvillei, natural 



size. After BRONGNIART. 



cies are known, the CEningen beds of 



Bavaria 'are celebrated as having furnished 844 species, des- 

 cribed by the illustrious Heer. 



Pleistocene species are supplied by the peats of France and 

 Europe, the lignites of Bavaria, and the interglacial clays of 

 Switzerland and Ontario, Canada. 



Silurian and Devonian. The oldest fossil insect known 

 consists of a single hemipterous wing, Protocimex, from the 

 Lower Silurian of Sweden. Next in age comes a wing, 

 Palceoblattina (Fig. 294), of doubtful position, 1 from the 

 Middle Silurian of France. Following these are six speci- 

 mens of as many remarkable species from the Devonian shales 



1 There is some evidence, it should be said, that this species is not an 

 insect. Handlirsch denies also that Protocimex is an insect. 

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