On Metallic Minerals. 398 



appears to 1>c either in immediate contact ^'ith |M'imary dv 

 transition rocks or if any rock containing oi^anic rentains 

 is found above it, tl»ese remains always intlicate an older 

 formation than the red marl or neiv red sandstonc-^the only 

 one it could be mistaken for. Admitting that it is tlje old 

 red sandstone and that that rock is the last of the secondary, 

 ibe one beneath it must be of the transition class, wJiich its 

 textui^ and structure corroborates, the former too loose for 

 a primary rock and the latter too crystalline for a secondary, 

 besides which a similar aggregate as bas been described, 

 is associated with graphite, a mineral seldom met with above 

 4he transition class. This limestone possesses one character 

 that may be con^jidcred some what at variance with these 

 views, viz. when sti'nck it gives out a strong odoui* 

 of sulphur. 



5th. — In excavating a lock-pit at Brewer's nulls, Mf. 

 Burrows met tvith the following rocks in the order set 

 tiown. He is not positive, however, that some of tt»em were 

 not boulders, but thinks that if they are they mu£t be very 

 large ones. The su|)crincuinbent rock forn)s a stratum of 

 about one foot thick, adapting itself to the shape of the 

 mass it rrsts upon. It is a crystalline aggregate composed 

 of black hornblende, which predominates, mica, felspar and 

 <piart'/. The rock it lies upon is a crystalline limestonie, 

 resembling No. 1, but liot so loose in its texture. If these 

 rocks are in situ and their relative i>osition correctly given, 

 the fact has very much the appenrancc of a secondary trap 

 overlying transition limestone. Large rhomboidal ci\stals 

 of felspar were also struck from a rock in place in this pitj 

 the whole is crowned by nine or ten feet ol very slillclay. 



(illi. — On the west side of Catara«pii creek, iinmediutely 

 opposite Brewer's upper saw mill, very fuic bpcciniens of 



