208 



TRANSACTIONS OP THE 



basin, a general observation maybe made, that wherever 

 a horizontal position (which often prevails apparently) 

 is not maintained throughout this parallel, there exists a 

 depression pointing towards this coal district. Conse- 

 quently, there is no probability that the mineral beds 

 are prolonged to the north ; and as has been before sug- 

 gested, we nsust continue to regard this area as the ter- 

 mination, in this direction, of the great bituminous coal 

 region. 



The subjoined diagram illustrates the • geological cir- 

 cumstances to which I have alluded, and the prolongation 

 of the old red sandstone group, which is here 6 or 7000 

 feet thick, from beneath theTiogacoal basin. PI. 8, fig. 5, 



A large portion of these red sandstones, and the lower 

 red argillaceous red sandstones and shales, are crowded 

 with producta and crinoidal remains ; and occasionally 

 fucoides and caryophyllea, pectens and spirifera are in- 

 terspersed. 



IRON ORES 



[Argillaceous CarhonaU of Iron) — Occur in several 

 beds, under diiferent modifications, instratified as usual 

 with coal, fire clay, and the common carboniferous 

 rocks. They comprehend the three varieties, known 

 to miners under the denominations of, veins, or con- 

 tinuous parallel seams ; pins^ or kidney-shaped concre- 

 tions ; and balls, or larger detached, oval, flattened 

 masses, of from one to two or three hundred weight, 

 sometimes irregularly dispersed in the mine ground, but 

 commonly in courses. Those of the first description are 

 the least, and of the third mentioned the most prevalent. 

 The kidney ore (the siderose or lithoid spathic iron of 

 Mr Clemson) is, I believe, commonly the leanest, though 

 readily convertible into fine melting iron ; the veins 

 are the most siiicious and infusible ; and the balls (sphere 

 sidereit) are the richest, producing a bright grey iron, 



4 



