78 Scientific Intelligence. 



position resemble some varieties of coal of the Carboniferous 

 system. 



2. Why ewe there no Fossils in the strata preceding the Cam- 

 brian ? — This question is answered, in the Proceedings of the 

 Philadelphia Academy of Natural Sciences, by Mr. Charles Mor- 

 ris, by the suggestion that the earliest animals like the youngest 

 stage of animal life generally had no hard parts to preserve ; 

 and that the sudden appearance of tribes was simply the appear- 

 ance of species having hard or stony secretions. One difficulty in 

 the way of the theory is presented by the existence of limestone 

 formations of great extent in the Archsean which most geologists 

 suppose to be of organic origin, and the existence also of phos- 

 phate of lime in large quantities which also is material of possible 

 organic origin. These facts, although of uncertain bearing, throw 

 doubts into all speculations on the subject. 



'3. Cone-in- Cone Structure. — Mr. John Young in a paper read 

 before the Geological Society of Glasgow (Geol. Mag., June, 

 1885), arrives at the conclusion that the cone-in-cone structure, 

 common in certain fine-grained sedimentary strata, consisting 

 chiefly of calcareous material, clay and iron, is due to the upward 

 escape of some gas generated in the deposit while it was in process 

 of formation, each ebullition of gas producing a new layer. The 

 cone is invariably found with the apex downward, and the author 

 states that between the successive layers there is always a thin 

 film of clay and also an axis of clay to the cone. The transverse 

 wrinkling on the layers is attributed to a creeping downward of 

 the plastic material through gravity. In the Scottish coalfield 

 the structure occurs in strata of freshwater or lacustrine origin. 



4. Aerial formations. — As the loss of China and similar depos- 

 its of other countries have been supposed to be of aerial or " Eolian" 

 origin, the following facts from the Records of the Geological 

 Survey of India, vol. xviii, p. 517, 1885, are interesting, as they 

 illustrate the general truth that deposits so made never have 

 for long distances a fiat horizontal surface or horizontal stratifica- 

 tion. "Aerial formations in the shape of blown sand cover large 

 tracts in these wide valleys (in Beluchistan), and practically all 

 the level country between Nushki and Helmund is covered with 

 sand-hills. It is characteristic of them that they generally form 

 low hills of crescent shape, with the horns and the scarp to lee- 

 ward ; the inclined plane formed by the currents of air are there- 

 fore generally dipping westward and show a rippled surface, re- 

 sembling closely the accumulations of drift snow on the Him- 

 alayas." 



5. Irish and Canadian Rocks compared. — In a paper by Mr. 

 G. H. Kinahan, in the Geological Magazine for April, 1885, the 

 characters of some Irish and Canadian Archsean rocks are dis- 

 cussed. He concludes that some of the gneissic Canadian rocks 

 are very similar to Irish metamorphic rocks that are not Archaean 

 but of different later periods, as Cambrian and Lower Silurian. 



