. yet they also Berve as a 

 \i cut; the weatherii tits. 



the country u such that outcrops are 

 r of tl. tation may often serve a- a clue 



In New Yurk the sur- 



lually C . lacial drift and Ikiht the bed rock 



on tin- rowth, as it does in the southern 



sidual imon. Streams which disap- 



. and calca - may also be looked on as evi- 



; hit th« lime rock. 



In tearchi calcart . if the eply lilted, 



it i- follow a line at right I to the strike, thus p; 



the different upturned beds. In regions 



of little or ii" dip this plan is vain* id a careful inspection 



mu- t ravines, valleys, and railroad cuttings. If the 



:j>, the apparent thickness of the rock bed at the surface, 



Bured at right a will be much greater than 



I thick he difference being greater the less the dip. 



A rapid c irmining the real thick t beds whose 



by the following rule: multiply iV of the ap- 

 parent tli i< by I of th( 3 ee of dip. Thus, if the apparent 

 aeafi et, and the dip 15°, the actual thickness 

 L2 Bf H x 3 25 feet. 



I OLOE or I.IMKSTOXKS 



An 3tone would be white, that being the 



natural cite, but most lim< - are colored either 



id <t o The former gives yellow, brown, 



. depending on the form of combination and 



stage of oxidation; while or matter colors the limestone 



gra A aall p< of organic matter may 



•r a li: \\ the black limestone of Fairhaven con- 



■f impuritii 



