GEOLOGIC FORMATIONS 743 



is one of tlie tliree formations in which Walcott found fossils. Its iden- 

 tification at the type locality as well as in Mnmm Peak is based on in- 

 disputable fossil evidence, and the formation directly underlying it in 

 Mumm Peak must, therefore, be the "Hota/^ That this is so is further 

 proved by the presence, below the Mumm Peak ^^Hota," of a series of 

 quartzitic sandstones comparable with the Mahto; and this section (Che- 

 tang, "Hota," and Mahto), reading from the top down, overlies, in one 

 unbroken, perfectly exposed section (§§ 16 and 32c), the beds in which 

 Walcott secured the "JSTew LoAver Cambrian subfauna" and which he 

 thought to be the "Hota" of Hota cliff. 



For the sake of clearness, I have used the term "Hota'^ in speaking of 

 this limestone in the preceding pages, but we have in this paper discarded 

 the term "Hota'^ and adopted the name Adolphus, for the following 

 reasons : 



(a) Without fossils or observable upper and lower contacts, we can not 

 be at all sure that the ^^Hota" even outcrops in the ridge named, but it 

 does outcrop in the cliffs of Mumm Peak above Lake Adolphus in ob- 

 servable relations to the overlying Chetang and the underhdng Mahto 

 (§§16 and 32c). 



(b) The published descriptions of the '^'Hota'^ are based on exposures 

 of the "Tah" (§30^). 



(c) The real "Hota" (the limestone immediately underlying the in- 

 disputable Chetang, which forms the summit of Mumm Peak) is de- 

 scribed, located, and given the name Mumm (§§26 and 32c). 



(d) The fossils credited to the "Hota," and these include a very im- 

 portant assemblage of Lower Cambrian fossils, did not come from the 

 "Hota," but from the "Tah" (§§ 30c, 30^, 32c-e). 



(c) The "Hota" is described as Lower Cambrian, but it is so referred 

 on the basis of fossils occurring a thousand or more feet lower in the 

 section (§ 8a) and of a "New Lower Cambrian subfauna" which occurs 

 2,500 feet below (§ 30^/). The "Hota" (Adolphus) is Middle Cambrian 

 in age. 



MAHTO SANDSTONES {% SI) 



(§ 31a..) The Mahto sandstones are described by Walcott as occurring 

 between the more or less calcareous "Tah" (= Mural) limestone forma- 

 tion beneath and the similar, though more limy, "Hota" (= Adolphus) 

 above. It was credited at first with the "new Lower Cambrian subfauna" 

 which he later took out of the Mahto and assigned to the overlying 

 "Hota" (§§30c, d, e, S2d, e). 



(§ 31&.) The Mahto is described by Walcott as unfossiliferous and the 

 boundaries we have dra^vn (§§ 30e, /, g, 32e) leave it without fossils as 



