HQ LA TOUCHE: GEOLOGY OF NORTHERN SHAN STATES. 



universally distributed through the rocks that almost every fragment 

 that one breaks open contains portions of the detached plates. They 

 must have literally swarmed in the seas of that period. In Spiti 

 and Kumaon, on the other hand, though the rocks have been 

 thoroughly searched, not a single specimen of this class of organism 

 has been discovered. The trilobites are almost equally conclusive. 

 Of the Himalayan forms Mr. Cowper Keed observes : — 



" The scarcity of trilobites is a remarkable fact ; with the exception of 

 one or two individuals, no examples of this group occur on any other horizon 

 but No. 2 . . . . The small size of the trilobites is noticeable, none attain- 

 ing such dimensions as are usual amongst Ordovician Cheiruridae, Asaphidae 

 and Illaanida?. 1 " 



It is true that he also calls attention, in his Burmese Memoir, 

 to the " rarity of the trilobites " as one of the characteristics of 

 the Burmese fauna, 2 but this remark was made before the discovery 

 of the rich trilobite localities and the numerous genera found there- 

 in by Mr. Coggin Brown and myself during the last two season's 

 work in the Shan States, and no longer holds good ; while many 

 of the specimens of the genera mentioned above, and of others 

 collected by us, will compare favourably in point of size with those 

 from the Ordovician beds of Great Britain or of the Baltic. Re- 

 presentatives of no less than fifteen genera are now known to 

 occur, and when it is remembered that these were collected from 

 no more than a few square feet of rock in each outcrop ac- 

 cidentally exposed, and at localities far distant from each other, it 

 is quite certain that further search will reveal the existence of 

 a much greater profusion and variety of these organisms. The 

 abundance of the detached eyes of trilobites in the Hwe Mawng 

 beds, already alluded to, points the same way. Of the bryozoa, 

 although individual specimens are common enough in Burma, 

 there does not appear to be anything like the same variety of 

 species as is found in the Himalaya, and only one, Rhinidictya 

 plumula, is common to both areas. Of corals 5 species are de- 

 scribed from the Himalaya, but the paucity of these fossils in Burma 

 is most marked. The mollusca, — lamellibranchs and gastropods, — of 

 which Mr. Cowper Reed has described 27 species from the Himalaya, 

 appear to be hardly represented at all in Burma : and it is only 

 among the brachiopoda that any points of resemblance are found, 

 while these lose much of their significance when we reflect that 



1 /bid, p. 164. 



2 Of. tit., Pal. lad., N. S., Vol. II, Mem. No. 3, p. 84. 



