~i 1 ROCKS OLDER THAN THE TACONIC SYSTEM. 



lithological characters of anj of n> members are; Mill I consider that il tends to remove 

 objections from the minds of some, to Bhow how it happens thai we find Blatea in the 

 Taconic system bo similai to those of the Gneiss or Primary system. It', however, the 

 doctrine 1 have advanced in relation to the origin of these slates is objected to, or is not 

 admitted as Bound, 1 will ask on mj pari hoM it happens thai talcose slate is found in the 

 conglomerate of the Old Red sandstone? [f there is anj better answer than the one 1 have 

 given ; if there is a better doctrine, let us have it. 1 say thai it' talcose slate, a sedimentary 

 mass, can be made in the era of the Old Red Bandstone, I Bee no objection to its being 



made at an earlier period bj the same prOCe88.* 



§5. Position and relations ok the taconic system. 



There is but one point which it is necessary to shew, in order to prove that the Taconic 

 rocks belong t<> a different period from those of the lower New York system; and this 

 being proved, the doctrine of metamorphiam, as usually applied and understood, is no 

 longer important, or even of any consequence. The Taconic roi ks may or may not be 

 metamorphic ; ihis maj be admitted, or it may be denied : it has nothing to do with the 

 question. Then texture ma\ have been changed since their deposition; but if so, it by 

 no means follows that they are of the period of the Hudson river slates, or of the lower 

 Silurian rocks. 



In proceeding to show the position of the Taconic system, I shall repeat in part the facts 

 stated in my report on the geology of (he northern counties; inasmuch as after a reexami- 

 nation, I find Inn few instances in which I have had occasion to make corrections. These 



• In these remarks, as I have touched lightly upon the coal-fieUl of Rhode-Island, I will permit myself to wander 



a little farther from the immediate Bubject of this essay. The doctrine thai the anthracite of this small basin is a 



metamorphic coal, has been promulgated by some of the abli at geologists "I this countrj and of Europe, particularly 



by Mr. Lveu The hypothesis is, that the bitumen which it i^ suppi mponent part of these 



beds of coal, has been dissipated by licit, or, in other words, burnt nut. To this doctrine the writer is not vet ready 



Id his assent, lor the following reasons: 1. The slates and o erate bear no marks of the action of heat 



(1 speak •■ which 1 have seen). The fossils are similar in texture to those of other coal-fields, and they 



are perfect sion or induration by caloric. The Catamites an- often in what son,, would 



call however, but in consequence of its origin. 2. If the bitumen was discharged 



by heat, then outfht the sulphur of the sulphuret of iron also to have disappeared, 3. If sufficient heat had been 



appl ize the bitumen of the coal, then ought thi to exhibit marks of having been burnt But 



said, farther, that the cojl is changed into graphite. Admitting tin- fact, does it prow that heat was the agent of 



this change- 9 It low, inasmuch as cast iron i phite without thit The 



doctrine I wish to maintain, is, tb.it il .is been thoroughly baked - pale all its volatile matter, 



t the rocks i aaving been baked or burnt. In this connexion, too, I 



I inquire, if in the original formal -. bitumen i£ that will be invariably 



prodm-ed : Admitting that bitui Island possess characters so 



ditli i item biium. that they cannot arise from pressure or other mechanical agencies ? The 



n, is in the existence of seams of quartz, traversing tin- cod ; not 

 injected in a melted state, but deposited from hot water or aqueous vapor holding silex in solution 



