PROCEEDINGS OF GEOLOGICAL SOCIETIES. 



207 



rock contains carbonate of lime, its structure has become sometimes 

 cellular or amygdaloid. 



Eocks or strata metamorphosed by granite are not observed to con- 

 tain zeolites ; as we have before remarked is the case with strata in 

 contact with lava or trap-rock ; but they often contain tourmaline 

 and the minerals which generally accompany the latter. Numerous 

 minerals are developed, however, by contact with granite, especially 

 when the metamorphosed rock is argillaceous. Some of the most 

 frequent are mica, made, staurotide, disthene, dipyre, garnet, horn- 

 blende, gi'aphite, and spiuelle. These minerals, although formed in- 

 contestably by the metamorphic action of granite, do not owe their 

 existence to the immediate contact of the eruptive rock. M. Delesse 

 supposes them to have been formed in a certain zone around the 

 granite at the moment the granite itself became crystalline. He 

 refers them to his " normal metamorphisms," which we described in 

 one of our previous papers ; and he remarks that the metamorphic 

 effects of granite extend to great distances, as normal metamorphism, 

 but, that, as phenomena of immediate contact, they are very much 

 more limited than we have hitherto been led to suppose. 



We have thus terminated our rapid sketch of the effects produced 

 on the different stratified deposits by the upheaval of igneous or 

 plutonic rocks. In a future article we will glance at the other side of 

 the question — the action that the different strata have exercised upon 

 the rocks that have uplifted them and modified their structure and 

 composition. 



PROCEEDINGS OF GEOLOGICAL SOCIETIES. 



Geological Society of London. — March 2Sd, 1859.— Prof. J. Phillips, 

 President, in the chair. 

 The folloYv'mg communications were read :— 



1. "On some Amphibian and Reptilian Remains from South Africa and 

 Austraha." By Thomas H. Huxley, F.R.S., Sec. G. S., Prof, of Natural History, 

 Government School of Mines. 



The author described in the first place the remains of a small Labyrinthodont, 

 Amphibian, -which he proposed to call Micropholis Stowii. The fossil was dis- 

 covered by Mr. Stow, and accompanied that gentleman's paper " On some Fossils 

 from South Africa," read before the Society on the 17th of November last, on 

 which occasion Prof. Huxley expressed the opinion that it would prove to be an 

 Amphibian, and probably a Labyrinthodont. 



It had been found impossible to work out the back part of the skull, so as to 

 exhibit the occipital condyles, but the characters of the few cranial bones which 

 remain, of the teeth, and of the lower jaw, and the traces of a largely developed 

 hyoidean apparatus, afforded sufficiently convincing evidence of the affinities of 

 Micropliolis. 



The generic appellation is based on the occmrence of numerous minute polygonal 



