■252 Di\ H. Woodward — Trilohites from Shcmtung, JV. Chuia. 



argillaceous layers between the single limestone strata correspond 

 to periods during which the conveyance of tine argillaceous 

 sediments produced a widespread turbidity of the water, so that 

 the Trilobites could take advantage of these periods to undergo their 

 -ecdysis whilst protected from the eyes of their enemies. 



What besides makes these slabs from Yen-tsy-3'ai particularly 

 interesting is their surprising agreement with the above-mentioned 

 plate from Peking, as the comparison of our pi. ix with Bergeron's 

 pi. xiii will show ; so that the latter might be presumed to come 

 from the same locality (as already mentioned, these slabs are 

 commercial articles in China). ^ However, a closer investigation 

 .shows small differences in the fauna, and for this reason I incline 

 to admit that the slab in fact comes '• from the mountains north of 

 Peking," where, according to Von Kichthofen (op. cit., p. 317), the 

 Sinic strata ai'e abundantly represented in the Nankon chain. There 

 is no doubt that this slab belongs to the same, or approximately the 

 same, geological horizon as those from Yen-tsy-yai. Regai-ding the 

 other question, whether all the 73 slabs from the latter locality 

 are of the same geological horizon, it may be mentioned here, in 

 anticipation, that almost without exception each of the slabs exhibits 

 representatives of all the species of Trilobites named in the collection, 

 save in the case of some of the rarer forms. 



In the memoir by Herr H. Monke, from which we have extracted 

 the foregoing account of the Trilobite-bearing beds of Yen-tsy-3'ai, 

 the author figures and enumerates the following genera and species, 

 namely : — 



1. Agnostus Koerferi, gen. et sp. nov., taf. 3, figs. 1-9. 



2. Liostracina Krauseri, gen. et sp. nov., taf. 3, figs. 10-17. 



3. Teinistion Lai\si, gen. et sp. nov., taf. 4, figs. 1-17. 



4. Teinistion Sodeni, gen. et sp. nov., taf. 5, figs. 1-4. 

 0. Drepannra Premesnili, Bergeron, taf. 5, figs. 5-19. 



6. DrejKuinra IvKtleleri, sp. nov., taf. G, figs. 1-14. 

 Embryonal forms, taf. 6, figs. 15-18. 



7. Steplmnocare Richthofeni, gen. et sp. nov., taf. 7, figs. 1-15. 



8. l^Stephauocare sinense, Bergeron (not figured).] 



9. Stephanocare, sp., taf. 8, figs. 1-4. 

 Drepanura Ketteleri (liypostome), figs. 5-Q. 



Drepamira Premesnili (hypostome), Bergeron, taf. 8, figs. 7-9. 

 Stephanocare Richthofeni (hypostome), taf. 8, figs, 10-11. 

 Slab (taf. 9). This slab, which agrees most exactly (even in 

 size) with that of which a part forms the subject of our Plate XIII, 



1 This seems less surprising when it is borne in mind that the higher classes in 

 China are very great connoisseurs of natural curiosities, which they purchase and cause 

 to be mounted as articles of bijouterie and vertn. Natural stones of all kinds cut and 

 squared up or cut and polished are sold in the shops of cities in China, often long 

 distances from the localities where the specimens were originally obtained. Mr. Crick 

 has referred to this circumstance in connection with the celebrated ' pagoda-stones ' 

 (sections of Orthoceras), which, being cut into slabs and mounted in frames to form 

 ornamental panels and screens, may now be met with as trade articles in almost any 

 part of China.— H. W. 



