13S 



HARDWICKE'S SCIEN CE- GOS SIP. 



ia others all the rocks. In some places the cleavage 

 is perpendicular, or neatly so, in tbe pure argillaceous 

 rocks, while as they become arenaceous it flattens ; 

 but in others the phenomena are exactly opposite. 

 Various other peculiarities in connection with slaty 

 cleavage might be enumerated, but sufficient have 

 been mentioned to show its complications. Twenty 

 years ago I believed I was master of the subject, 

 now I know my ignorance.— G. H. Kincihan. 



Occurrence of Phosphates in the Cambrian 

 Rocks. — At a recent meeting of the Geological 

 Society a paper by Henry Hicks, Esq., E.G.S., was 

 read on this subject. The author showed from 

 experiments that the Cambrian strata in Wales 

 contain a far greater amount of phosphate and car- 

 bonate of lime than had hitherto been supposed. 

 The results published by Dr. Daubeny some years 

 ago, and which have since received the support of 

 some eminent geologists, were proved therefore to be 

 entirely fallacious when taken to represent the 

 whole Cambrian series; for though some portions 

 show only a trace of these ingredients, there are other 

 beds, both interstratified with and underlying these 

 series, which contain them in unusually large pro- 

 portions. The author, therefore, objects to look 

 upon Dr. Daubeny's experiments as tending in any 

 way to prove that the seas in which these deposits 

 had accumulated contained but little animal life, 

 and that we had here approached the borders of 

 the lower limit of organic existence. He contended 

 that the presence of so much phosphate of lime, 

 and also of carbonate of lime, as was now proved 

 by analyses made by Mr. Hudleston, F.C.S., Mr. 

 Hughes, F.C.S., and himself, to be present in 

 series of considerable thickness in the Longmynd 

 group, Menevian group, and Tremadoc group, 

 proved that animal life did exist in abundance 

 in these early seas, and that even here it must be 

 considered that we were far from the beginning of 

 organic existence. The amount of phosphate of 

 lime in some of the beds was in the proportion of 

 nearly 10 per cent., and of carbonate of lime over 

 40 per cent. The proportion of phosphate of lime, 

 therefore, is greater than is found in most of what 

 have been considered the richest of recent forma- 

 tions. The amount of P 2 s was also found to 

 increase in proportion to the richness of the deposit 

 in organic remains. It was found that all animal 

 and vegetable life had contained it from the very 

 earliest time ; but it was apparent that the Crus- 

 tacea were tbe chief producers of it in the early 

 seas ; and of the Crustacea, the trilobites more 

 particularly. It was always found where they 

 were present, and the shell of some of the larger 

 trilobites, as now preserved, contained as much 

 as from 40 to 50 per cent, of phosphate 

 of lime. The analysis made by Mr. Hudleston 

 and the author of " llecent Crustacea " proved 



that they also contain P 2 s in very con- 

 siderable proportions. In the second part of the 

 paper the author showed that where intrusive dykes 

 had passed through or between the beds con- 

 taining the phosphate of lime, the beds for some 

 distance on each side of the dykes had undergone 

 a considerable change. Scarcely a trace of the 

 P 2 3 or of the lime was now to be found in them, 

 though it was evident that before the intrusions 

 into them had taken place, they, like the other por- 

 tions of the beds, had evidently contained both in- 

 gredients in considerable proportions. It was well 

 known that heat alone could not separate P^O,-, from 

 lime; therefore he found it difficult toaccouut for this 

 change in the character of the beds, unless it could 

 be produced by gases or watery vapour passing into 

 them at the time the intrusions took place. He 

 thought it even probable that the dykes, which in 

 some parts are found to contain a considerable 

 amount of lime and also of P2O5, might .have 

 derived these, or at least same portions of these, 

 from the beds through which they had been forced, 

 and which must have been broken up and melted 

 as they passed through them. There are no con- 

 temporaneous tuffs known in Wales of earlier date 

 than the Llandeilo beds ; and he thought these 

 dykes belonged to that period, and that they were 

 injected into the lower Cambrian beds after from 

 S,000 to 10,000 ft. of deposit had been superimposed. 

 In an agricultural point of view the author con- 

 sidered that the presence of so much phosphate of 

 lime in some of the series of beds must be a matter 

 of great importance ; and on examining the districts 

 where these series occurred, he invariably found the 

 land exceedingly rich. Mr. Hudleston gave the 

 results of the analyses made by him at the request 

 of Mr. Hicks. He found in a portion of dark grey 

 flaggy rock taken from close to a fossil 1*62 ; in a 

 portion of black slaty rock containing trilobites, but 

 in contact with trap, 11 ; in a portion of the shell of 

 a trilobite 1705 ; and in the trap above mentioned 

 0'323 percent, of phosphoric anhydride. A lobster- 

 shell dried at 100° C. gave 3 26, an entire boiled 

 lobster (uudried) 0'76, and a boiled lobster without 

 shell 0'332 per cent, of P 2 5 . If the analysis of au 

 entire lobster be correct, he estimated that a ton of 

 boiled lobsters would contain about 17 lb. of phos- 

 phoric anhydride. In the analysis of the shell of a 

 trilobite there appears to be a great excess of phos- 

 phoric acid, which Mr. Hudleston thought must be 

 due to substitution. 



NOTES AND QUERIES. 



Cats and Water.— W. Sharp is not a solitary 

 observer of the fact that cats will venture into water 

 after fish. A few years ago I was walking by the 

 side of a small river, when 1 noticed a cat crouching 

 on the bank, and evidently watching something in 



