456 MR. S. S. BUCKMAN ON THE [Nov. I903. 



Table VI. 



Approximate 

 maxima of 

 Heinene. deposits 



in feet. 

 Moorei \ . 



Dumortieria j 



Dispansi 50 



Struckmanni 70 



Striatuli 20 



Variabilis 100 



IAlli , 130 



Bifrontis 



Total 719 



Falciferi \ 150 



Taking, therefore, the various maxima of deposits in the South - 

 AVest of England, it is seen that the work accomplished during the 

 time of the Toarcian Stage is represented by a deposition of some 

 700 feet of strata. The time during which this work was performed 

 is divided into about nine hemerae, so that the time-value of a 

 hemera, on this evidence, is equal to the time taken to 

 deposit about 80 feet of strata on an average. 1 



VI. Retrospect. 



Now that the faunal contents of the various Sands are definitely 

 known, the old, much-debated question, whether the Sands are 

 Liassic or Oolitic, may be considered as settled. 



In different localities the Sands are of different 

 dates. Sometimes they are contemporaneous with what is called 

 Inferior Oolite elsewhere, sometimes with what is called Upper Lias 

 a few miles away. 



Taking the Toarcian Stage to include strata up to the deposit dated 

 hemera Moorei, and calling this ' Upper Lias ' in a general sense, and 

 taking the Aalenian Stage for deposits of later date = Lower Inferior 

 Oolite, then it may be said that the Northampton Sands and the 

 so-called ' Midford Sands ' (G 4) of the North Cotteswolds are early 

 Aalenian ; the Bridport Sands are in part Aalenian, in part Toarcian ; 

 the Yeovil Sands are Toarcian ; the Midford Sands of Midford 

 (Bath) are Toarcian, but "post -striatuli; the Cotteswold Sands, 

 so-called < Midford Sands (G 4) ' of the Mid- and South Cotteswolds 

 are Toarcian, but pre -striatuli. The Harford Sands of the eastern 

 part of the Cotteswolds are late Aalenian. 



It seems desirable to drop the term ' Midford Sands ' in its wide 

 sense. It suggests, as between strata of different localities, con- 

 temporaneity where there is sequence ; in other cases, sequence 

 where there is contemporaneity. The local names for the Sands 

 may be retained as useful, colloquial, stratigraphical terms. Where 



1 Strata of hemera acuti have not been considered — they are not definitely 

 developed in the districts investigated. 



