140 Analyses of Booh. [Feb. 



into the basis of the rock. The transition conglonierated rocks arc 

 grey-wacke, sand-stone, and lime-stone. He considers all these 

 as immediate deposites, for a similar reason with the primitive 

 conglomerates. The floetz conglomerates are sand-stone conglo- 

 merate, sand-stone, and trap tuff. The first and last he considers 

 as always immediate deposites; the sai d-stone as frequently so. 



15. On Porphyry. By I'rofessor Jameson. — Werner admits 

 into his system of geognosy five kinds of porphyry; namclvj clay- 

 porphyry, horn-stone-porphyry, pitch-stone-porphyry, obsidian- 

 porphyry, and pearl-stone-porphyry; all of which are prin)itive 

 rocks. The object of tliis paper is to show, that there exist like- 

 wise transition and lloctz porphyries. Transition porphyry lias a 

 basis of clay-stone or felspar. It contains crystals of felspar, grains 

 of quartz, scales of mica, and crystals of hornblende. It occurs 

 abundantly in Dumfriesshire, and between New Galloway and 

 Dumfries, where it alternates with grey-wacke, grey-wacke-slate, 

 and transition green-stone. Floetz porphyry has likewise clay-stone 

 or felspar for its basis, and contains crystals of common felspar, 

 glassy felspar, and quartz. It occurs in the islands of Arran, Roa- 

 say, and 8kye, and in the Ochils and Pentland hills. 



16. Miner alogical Observations and Speculations. By Professor 

 Jameson. — These observations and speculations relate to three par- 

 ticulars : 1. Stratification. This first speculation is rather of a 

 bold nature, as Mr. Jameson endeavours to explain in what manner 

 the crust of the earth was originally formed. His notion seems to 

 be, that the whole earth is a crystal, that the tabular masses or 

 strata arc the folia of this crystal. He even affirms, that these 

 strata meet under determinate angles, and are to be considered as 

 the same with the cleavage of common crystals. I am sorry that 

 in this very uncommon and novel view of stratification, I cannot 

 agree with the opinion entertained by my very ingenious friend. 

 The laws of crystallization have been studied "with sufficient care 

 and success to enable us to decide, without hesitation, that the 

 earth cannot be a crystal, and that its strata are not the same with 

 the folia of crystals. The figure of crystals is owing to the figure 

 of their ultimate particles, and the particular way in which they 

 unite. Without chemical affinity and chemical combination we 

 can have no crystal. The different plates of a crystal are arranged 

 by the same law, and they are attached to each other by chemical 

 affinity. But what chemical afiinity can unite the difTerent strata 

 of the earth with each other ? Where is the chemical affinity 

 between lime-stone, slate-clay, coal, and sand-stone, for example ; 

 or between sand-stone, green-stone, slate-clay, or basalt? Yet what 

 is more common that such alternations. To say that the strata 

 form every where regular angles with each other, as happens with 

 the plates of a cryst;il, is saying what ^las never been proved or 

 even rendered j)robable. The last part of the speculation, that 

 different strata are often of simultaneous formation, i?, to a cirtain 

 extent at least, more probable than the former part : thougli I llii:ik 



