82 NATURAL SCIENCE [August 



and the Shale, lie several seams of so-called coprolites or nodules of 

 phosphates of lime. The seams vary in thickness from three inches 

 to eighteen inches, and all are formed of these nodules closely com- 

 pacted. We have had an opportunity of assisting at an analysis of 

 these nodules, from which it was demonstrated that not only are 

 they remarkably free from iron, but that they are ten per cent, 

 richer than are the imported Belgian samples. It must not be sup- 

 posed that these seams are peculiar to Handley's Pit only — they 

 extend uniformly throughout the middle hills of Lincolnshire, and 

 are exposed in most of the pits from Lincoln to Grantham. If 

 properly exploited the phosphate industry in Lincolnshire might be 

 made second only to that of its great iron mines and foundries." 



Humbee Mud 



Theee is mud in the Humber estuary, mud and sand, and a great 

 deal of it. Where does it come from ? 



This is the question that the Hull Scientific and Field Natu- 

 ralists' Club set itself to discuss on April 13th, the discussion being 

 opened by its energetic secretary, Mr T. Sheppard. The usual 

 reply that the mud comes from the tributary rivers, Ouse, Trent, 

 and Hull, is soon found to be inadequate. The mud is accumu- 

 lating so rapidly that the material brought down by the rivers is 

 insufficient to account for it. Not only sand and mud banks but 

 dry land is continually being formed. Reed's Island, between 

 North and South Ferriby, was, some twenty-five years ago, com- 

 paratively small, with a plot of grass on which a few cattle were 

 reared. Now it is hundreds of acres in extent, has an enormous 

 number of cattle grazing upon it, and is still growing. As for the 

 accused rivers, their waters are comparatively clear and hold but few 

 particles in suspension. Such detritus as they do transport is for 

 the most part redeposited on their own banks, or in the alluvial 

 flats so characteristic of the Ouse and Trent. It is, however, 

 noticed that the water near the mouths of these rivers is far more 

 muddy when the tide is flowing up them ; and this suggests that 

 the mud may be brought into the Humber from the sea. 



The waters of the North Sea are continually washing particles 

 of rock, sand, and mud in a southerly direction, and slowly but 

 surely the material on the Yorkshire coast is travelling southward. 

 It never travels in a northerly direction. As is well known, the 

 beach around Flambro Headland is strewn with masses of chalk of 

 all sizes, which have been dislodged from the cliffs. These can be 

 seen in plenty in Bridlington Bay and further south, though natu- 

 rally getting less plentiful as they get Humber-wards. Hardly any 

 chalk boulders are found north of the headland. This proves that 

 the beach-material travels southward. Now the cliffs of the Holder- 



