Peacock : Naturalists in South Lincolnshire. 



At Navenbv the passage downward from the Oolites through 

 the Northampton sands to Upper Lias clay was seen in an 

 interesting- section close by the churchyard wall, where a ditch 

 had recently been re-cut. The so-called Fish and Insect beds at 

 the base of the Upper Lias were examined in a clay-pit at the 

 foot of the escarpment, and good specimens were obtained 

 crowded with the characteristic fragments of Inoceramus, 

 These fragments have the appearance of scales of fish and 

 wings of insects, and have given the specific name to this base- 

 ment bed of the Upper Lias. 



Occasion was taken when searching for the Middle Lias 

 beds to refer to the absence of the marlstone for a distance of 

 12 miles along the cliff escarpment, between North Carlton on 

 the north and Wellbourn on the south ; and to the palaeonto- 

 logical zones which immediately underlie the Marlstone Rock 

 bed. Reference was also made to the interesting changes 

 which take place in these zones, and in fact in the whole 

 Jurassic series of Lincolnshire between the south and north of 

 the countv. These differences in the strata and range of fossil 

 forms often make it very difficult to assign boundaries to the 

 formations. As a typical example the following diagrammatic 

 sketch was given in illustrating the boundary between the 

 Middle and Lower Lias. 



The southern, middle, and northern parts of the county are 

 covered by geological survey sheets Nos. 70, 83, and 86 respec- 

 tive! v. In sheet 70 the two Zonal Ammonites, spinatus and 

 margaritatus, are embraced in the Middle Lias, the Capricornus 



Naturalist, 



