R^SUMI^:, AND GENERAL DISCUSSION. 545 



rets of the various metals occur all over the world iu vast quantity, and 

 as low down as mining has ever penetrated. The facility with wliich the 

 metallic sulphurets are decomposed by water when at a high tempera- 

 ture, and again the liability to decomposition, in a variety of ways, of 

 the sulphuretted hydrogen thus formed, are matters familiar to those 

 who are moderately well acquainted with elementary chemistry. "We 

 need, iu this connection, only state the simple fiict, that, only a few 

 years ago, nine tenths of all the sulphur consumed in the world was 

 obtained from a region where all the facts show clearly that this sulphur 

 was the result of volcanic agencies. This alone is sufficient evidence on 

 the point iu question. 



It has also been claimed that the presence of apatite in the Azoic 

 rocks was an indication of the existence of life at the time these rocks 

 were deposited. Since phosphoric acid, probably largely in the form of 

 phosphate of lime, has been found in almost every kiud of eruptive 

 rock, including granite, porphyry, and both ancient and moderu lavas, 

 it seems that the theory which makes this mineral necessarily the 

 result of organic agencies, is not supported by facts. The earliest 

 plants and animals which required phosphoric acid for their develop- 

 ment cannot have taken it originally from the atmosphere, since it does 

 not exist there. They must, therefore, have obtained it from the earth, 

 unless we are willing to admit that it was created by them. 



In view of all that has been set forth iu the preceding pages, we con- 

 sider that we are fully justified in saying that the results of geological 

 investigation during the past thirty-five years have given no encour- 

 agement to the idea that below the well-known Primordial zone — the 

 Potsdam sandstone of American geologists — there is another series of 

 fossiliferous rocks. We think that the nomenclature of the forma- 

 tions should be made to correspond with the actual facts, rather than 

 with views which have no other than a theoretical basis. It would no 

 doubt be in hannony with the ideas and wishes of many palaeontolo- 

 gists, that there should be found a series of rocks occupying the position 

 of the Azoic system replete with organisms of a lower type than that 

 of the " Primordial Fauna ',' of Barrande.* This desire has, no doubt, 

 powerfully contributed to the general acceptance of the Eozoon as a 

 relic of life, although — as it seems to us — the entire absence of forami- 

 niferal life in the lowest Silurian, throughout the world, places the 



* "In his address to the British Association at Bath, he [Lvell] naturally 

 revelled with delight at the discovery of the Eozoon Canndcnse in the Lower Lau- 

 rentian." — Murch, in Geol. Mag., IL (186.t), 98. 



VOL. VII. — NO. 11. 35 



