NJDEP - NJGS - First Annual Report of the Geological Survey of the ...

posed of one or more of the following simple minerals :--feldspar_quartz, hornblende, and mica.. They occur in veins_dikes_ great irregular masses traversed by joints and divisionalplanes, constituting mountains_ ridges, &c.AquEous Rocg_s.--The aqueous rocks arb those whichhave been formed by the agency of water, from the disintegratedparticles of other rocks transported by currents, and depositedas sedimcnt, in the form of strata, beds, layers, laminm_&c. They very often contain organic remains of plants andanimals.META_IOI1PHIC RocKs.--The metamorphic rocks are thosewhich have been formed by aqueous agencies, and subsequentlyso much altered in their texture by the action of heat_as to resemble igneous rocks. They contain no visible organicremains.The above is a very general classification of roeks_ derivedfrom their origin. The)- are subdivided into groupscalled systems_ according to their relative age. It is to be regrettedthat much confusion prevails in regard to their nomen-.elature.Every country, and almost every geologist, has a particularsystem of names, derived either from characteristic fossils,localities, or some lithulogical peculiarity of the rocks. Thosemost generally used and understood in this country_ are thnnomenclature of the English geologists, and that proposed bythe geologists of the New York survey. Thd former is chieflyderived from localities in Great Britain, the latter from locali*ties in N'ewYork where particular groups of rocks arc welldeveloped. As this was the first attempt at a complete classificationof the rocks of this country_ it has been generallyadopted in different States of the Union, and undoubtedly willremain as a standard of comparison. Geologieal investigationarranges and classifies the roeks_ represents their extent, thickness,and order of arrangement_ by means of sections, profiles,&c. ; points out and describes the valuable mineral deposits ofeach formation, and the manner in which they may be workedand applied to various economical purpose_ But in order toiLLNEW JERSEY GEOLOGICAL SURVEY