36 



Mr. W. J. Hamilton and Mr. H. E. Strickland, on the Geology of 



Mineralogy. — To the mineralogist the Catacecaumene presents rather a barren 

 field. The scoriae and lava are of ordinary character ; the latter contains olivilie 

 and augite, but no other crystalline minerals were observed. 



Thermal springs. — In a valley about a mile north of the Hermus, and six miles 

 N.N.E. ofKoola, are some remarkably copious hot springs, rising in the lower beds 

 of the lacustrine limestone. The water is perfectly tasteless, and forms no deposit 

 or sediment whatever. The thermometer rose at the lowest spring to 123° Fahr. 

 A short way to the east, in the centre of the ruins of an undetermined ancient city, 

 are two other sources, at which the thermometer rose respectively to 133° and 137°. 

 They rise out of a crevice in the calcareous tufa, and exhibit a slight development 

 of sulphuretted hydrogen gas. 



Comparison of the Catacecaumene with Auvergne. 



No well-informed geologist can fail to be struck with the numerous and remark- 

 able analogies between the Catacecaumene and the volcanic district of Central 

 France, so elaborately described by Messrs. Scrope, Lyell, Murchison, &c. We 

 will here present, in a tabular form, a few of the chief points of resemblance be- 

 tween the two districts. Some of these analogies may perhaps be only accidental 

 coincidences, but the majority of them afford instructive examples of the univer- 

 sality of Nature's laws, whereby similar causes produce similar effects, even in the 

 most distant regions. 



Points of agreement between the Catacecaumene and Auvergne. 



1. In both cases, clusters of extinct volcanos occur in the in- 

 terior of continental tracts, remote from the sea. 



2. They are referable to several distinct periods, all subsequent 

 to the commencement of the tertiary epoch. 



3. They rise out of rocks apparently of the primary epoch. 



4. The direction of the volcanic zone coincides with the strike of 

 the older rocks through which it is ejected. 



5. The volcanos rise near the margin of a tertiary lacustrine 

 basin, which they have partially overspread with basalt and 

 lava. 



6. Eruptions of an early date have poured forth basalt over the 

 lacustrine deposits, prior to their denudation. 



7. Extensive valleys of denudation have been excavated in the la- 

 custrine deposits, which now form tabular hills capped with 

 basalt. 



EXAMPLES. 



Catacecaumene. 



Auvergne. 



Three periods. 



Numerous success- 





ive periods. 



Mica-schist. 



Granite. 



E. by S. to W. by 



N.toS.andN.N.W. 



N. 



to S.S.E. 



Basin of the Cata- 



Limagne d'Au- 



cecaumene. 



vergne. 



Basaltic plateaux 



Plateau ofChateau- 



N.E. of Koola. 



gay,Gergovia,&c. 



Valleys of the Her- 



Valleys of the Al- 



mus and A'ineh- 



lier and its tri- 



chay. 



butaries. 



