238 Mr. Bubble's Synopsis of the Newcastle Coal Field. 



CONCLUDING OBSERVATIONS. 



In conclusion, I beg to be permitted to observe, that I merely intend 

 the Sections of our Coal Strata, which accompany this paper, and the 

 descriptions of them, as a partial sketch of the Geology of the Newcas- 

 tle Coal-field. My immediate object having extended no further than 

 to place the knowledge of the several seams of Coal in a more familiar 

 point of view, than has hitherto been done. 



The little which I have done, however, towards illustrating the gene- 

 ral formation of the Coal strata of our district, shews, that much more 

 remains to be done, and that the subject forms an extensive field for 

 geological investigation. 



I have touched but slightly on the various changes in the Sandstone 

 strata, which occur on the several lines of Section, but it is worthy of 

 observation, that they increase both in number and thickness towards 

 the rise or crop of the strata, and that the number and thickness of the 

 Metal Stone strata increase in the opposite direction. What is the 

 cause of this? Has the law of gravitation operated in the deposition of 

 those strata, and produced this effect ? Some light might be thrown 

 upon this branch of the subject, probably, by ascertaining the specific 

 gravities of the several strata at their crop and extreme dip. 



The seams of Coal are, in some degree, governed by the same law ; 

 as we find some of them, particularly the High Main Coal, thickest 

 towards its crop. 



In the series of the seams of Coal which I have given in the table, I 

 have not noticed that described by Mr. Wm. Hutton, under the Red 

 Sandstone at Clowsdon-hill Quarry, on the north side of the Main 

 Dyke, near the village of Killingworth. As this is the Red Sandstone, 

 on which the Magnesian Limestone reposes, there can be no doubt of 

 this seam of Coal, which lies immediately below it, being the first in our 

 series. But as it has not yet been worked in any part of the district, I 

 have not placed it in the Synoptical Table, which is only intended to 

 shew the workable seams in the district. 



