A HISTORY OF NORTHAMPTONSHIRE 



successful in its object, the incidental information then obtained is most 

 interesting. An abbreviated section is given below. 



Top of 

 Section at Orton in bed from 



sea-level 



Upper Lias, including soil and silt 



Middle and Lower Lias 



RHitTic (White Lias and Black Shales) 



Keuper : Sandstone and Breccia 



Old Land Surface 



Volcanic Rock : Quartz-porphyrite showing an eroded surface ; 

 distinct cleavage at an angle of i8° with the axis of the core . 



Greatest depth 



Quartz-porphyrite (or dacite ?) occurred in both the Keuper breccia 

 and Rhastic conglomerate (White Lias), clearly indicating that after the 

 volcanic rock at Orton had been covered with newer deposits the same 

 rock was still exposed not far away ; that is to say, Orton was not the 

 highest part of the volcano, or not the only one. 



The Cambrian and Silurian Periods 



The Cambrian and Silurian periods may be passed over with the 

 remark that, considering the relatively small thickness of the earth's 

 crust at present pierced by borings in Northamptonshire, and for other 

 reasons, one or both of these formations may be supposed to occur below 

 the ascertained rocks. 



The Old Red Sandstone (?) 



The oldest stratified rocks that have been encountered in situ in 

 Northamptonshire consist of coarse red sandstones, grits and marls, 

 beheved by Mr. Etheridge to belong to the Old Red Sandstone period, 

 though, as remarked by Prof Judd, they may belong to the Carboniferous 

 formation ; in the absence of fossils the point must remain undecided. 

 Prof. Bonney says that undoubtedly the material was derived from 

 granitoid rocks of Archsan age.' 



The rocks here referred to were encountered in the deepest boring 

 so far made in Northamptonshire (994 feet), at a place near to the canal 

 and railway between Gayton and Bugbrook, some five miles south-west of 

 Northampton, and two miles north-west of Blisworth station. The boring 

 was a trial one for water by the Northampton Waterworks Company. As 

 with the Orton boring, an abbreviated section is given from information 

 then obtained. 



* Henry John Eunson, 'The Range of the Palseozoic Rocks beneath Northampton,' 

 Quart. 'Journ. Geol. Soc. (Aug. 1884), vol. xl. p. 492. 



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