— 118 — ' 



or marl, in the other mines of the Kargalinsk district 

 the same phenomena are repeated, upon which and upon 

 other results of his researches Mr. Rickard has foun- 

 ded a theory of the origin and method of deposition of 

 the copper, which i believe he is engaged in preparing 

 for publication. 1 quite agree with him that the beds of 

 copper ore mark the courses of fresh water streams of 

 Permian age. They are destitute of all marine organic 

 remains. Their characteristic, and I may say, almost their 

 sole petrifactions are Calamités, Lepidodendron (found 

 rarely), leaves of Aroides crassispatha (Kutorga), conifer 

 trunks and twigs, a Unio closely allied to, if not iden- 

 tical vvith, Unio umbonatus (Fischer), Platysomus and 

 Amblypterus (the latter however not as restricted by 

 Troschel) remains of Labyrinthodonts and lastly, isola- 

 ted, fragmentary remains of theodont reptiles, which 

 though rare and sadly imperfect, infuse into the mind of 

 the palaeontologist an enthusiasm which compensates for 

 much weariness in searching for traces of former life in 

 these monotonous rocks. Humeri with entepicondylar fo- 

 ramina and jaws with teeth differentiated by form and 

 position into molars, canines and incisors illustrate the 

 existence here of Permian reptiles with these mammalian 

 characteristics. The genetic history of mammals, when 

 established, will derive important illustrations from these 

 reptilia. Professor Owen has seized the Permian reptiles 

 of Russia (Rhopalodon [Fischer] and Deuterosaurus [Eich- 

 wald] as genera of his order Theriodontia *) Remains of 

 other genera from the Kargalinsk steppe support his 

 conclusions. 



*) Quart. Journ. Geolog. Society Aug. 1876. Vol. XXXII. pp. 

 352 — 363. 



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