236 STRATIGRAPHY 



handed over to me for examination. Unfoi-tunately the sections were not cut in 

 series, for it was not at first supposed that they were of such great palgeontological 

 interest. Since the specimens are very fragmentary, I have felt it advisable to 

 describe them first of all seriatim with reference to the photographs. In this 

 description I have given numerous references to the Memoir * on the Archceo- 

 cyathince, published by the Royal Society of South Australia, completed earlier 

 in 1910. 



The bearing of this discovery on the climate of the Cambrian Age is, I under- 

 stand, being investigated by Professor David ; but I cannot refrain from drawing 

 attention to the geographical position of this Archceocyathince horizon. In the 

 Memoir (p. 69) I give a diagram (Fig. 3) illustrating the extra-tropical character of 

 the localities. Hitherto, althougli none have been discovered in lower latitudes than 

 30°, the occurrence nearest the Poles had been that of Waigatch Isle to the north 

 of Russia (lat. 70° N.). The present specimens come from much higher latitudes, 

 probably from 85° S. — for the actual specimen was not found in situ, but among 

 moraine material near the Cloudmaker. 



One may hazard the speculation that in the Cambrian, the period of luxuriant 

 life at the Poles was correlated with conditions of great heat at the Equator (far in 

 excess of those obtaining at present), which may be shown by desert sandstones such 

 as are so characteristic of the Triassic. It will be most interesting in this connection 

 if a Triassic fauna and flora is found to be developed in Antarctica. 



DETAILED DESCRIPTION OF SPECIMENS IN MICROSCOPIC 



SECTIONS 



Plate LXXVI. Fig. 1. A cross-section of a small regular ArcJueocyathus only 

 one-third of a millimetre in diameter. It is of interest as being one of the smallest 

 specimens described, but yet shows every characteristic of the mature ArchcBocyathus, 

 such as the rather dense outer wall and the highly perforate inner wall and septa. 



Here the data seem to show that in these organisms there is no simple calcareous 

 beaker-form (without septa), but that the youngest skeleton has a number of regular 

 septa. 



As in the South Australian specimen the primitive number of septa seems to be 

 six, so far as we can reconstruct the cup shown in the figure. 



Plate LXXVI. Fig. 2. This is an oblique sagittal section of a very young 

 cup. It is extremely interesting ; perhaps one of the best sections so far noted at 

 this stage. The section shows the outer wall, several septa, and the large pores of 

 the inner wall, for in the ujjper portion the .section is practically parallel to the 

 inner wall. 



In photo 46, Plate VIII. of my Memoir (on the left towards the top), is a cup 



• Griffith Taylor : Mun. E. Soc, South Australia, 1910, ii. part 2. 



