A HISTORY OF NORTHAMPTONSHIRE 



The Upper Lias varies very little in thickness throughout the 

 county, and the zones are well marked. The map will show where the 

 Upper Lias is exposed, and as the clays are largely used for brickmaking, 

 the neighbourhood of any town or large village situated on it, or on the 

 Northampton sand, will generally have one or more exposures. 



The Lower Oolites 



The Lower Oolites consist of ironstones, sandstones, clays, marls and 

 limestones ; and since sandy strata, and even some limestones, indicate 

 comparative nearness to the source of the material, they are seldom as 

 persistent in thickness and superficial extent as argillaceous beds. In 

 addition, oolitic limestones probably indicate warm, agitated, and therefore 

 shallow water during the time of their formation. There was so much 

 coquetting of the land with fresh and salt water about this period that 

 we can scarcely speak of the series of Lower Oolitic rocks as we did of 

 the Lias, but will make such references to the physical conditions then 

 existing as seem called for, in the appropriate place. The beds can be 

 usually identified without the aid of characteristic fossils. 



The Inferior Oolite 



Inferior is a term used to designate position only. In our small 

 scale map the whole series is represented under one colour. 



TYPICAL SECTION OF INFERIOR OOLITE SERIES 



* Water-bearing beds. 



The Northampton Sand 



The Ironstone Beds constitute a valuable source of iron, and are 

 consequently worked at many places. The red ore consists largely of a 

 hydrated peroxide of iron (Brown Hsematite or Limonite) ; it may present 



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