76 



HARDWICKE'S SCIENCE-GOSSIP. 



Quartz is one of the hardest minerals. Steel 

 cannot scratch it. So that it follows as easy 

 corollaries that quartz sand has resisted trituration 

 longer than softer rock substances, and therefore as a 

 rule has not travelled so far from its original site as 

 softer and less dense rock material. Geologists, 

 recognising this fact, are accustomed to say, whenever 

 they meet sandstone in the earth's crust, that it 

 indicates proximity to ancient shores ; when they 

 meet with grit and gravel-beds, that they are nearer 

 still ; with pebble beds (conglomerates), nearer still ; 

 and when the fragments are (generally) larger and 



posure to the prevailing westerly or south-westerly 

 winds. In Sand Bay the distance occupied by sand- 

 tots is a mile and a half, from Woodspring to Kew- 

 stone. The soil inland is alluvium, lying upon 

 liassic limestones and shales. In Weston Bay the 

 distance occupied by sand-tots is a mile, from "the 

 Beach " to Uphill. Here also, the soil inland is 

 alluvium resting upon the lias. In the next bay, 

 Bridgwater Bay, the distance is five miles from 

 Brean Down to Bromham, and from Start Point to 

 Stolford, four miles. Here also there is a fringe of 

 sand-tots ; and here also the land is alluvium, resting 



Cleve on»^„ |m , 



limestone ridcc ''iwiw 

 Nailsea Moor 



i 

 Kenn Moor ^-* 







I 



Tote J 



Locking Moor 

 f. Uphill 



i+Brean %/,„.,„ 



'"Will 



«<o CE I 



w// '"!iiai«\»«»:i 



iUCTOKBC?!Y 



Moor 



Tots 

 Stolforb 

 ___^-*-'<'«ntHf Tl 



Polden Hills 



S8F 



Fig. 42. — Sand-tots along the Somersetshire coast. 



angular, that they have the debris of sea-cliffs them- 

 selves (breccias). 



Following the coast of the Channel until we reach 

 the harder cliffs of more ancient rocks on the north 

 and south, we have local deposits of sand derived 

 in part from the cliffs themselves, especially from 

 those older volcanic rocks which are largely com- 

 posed of quartz ; but we may pretty safely conclude 

 that in most sedimentary rocks there is an admixture 

 of quartz, although it may be so finely abraded as to 

 escape naked eye observation. 



In the formation of sand-tots, we have to consider 

 a few fresh facts. We find them in the Severn 

 Estuary in certain favourable places ; where the 

 tidal range is great, in deep bays, and with an ex- 



upon the lias. Beyond this point the shore rises into 

 low liassic cliffs, and the sand-tots cease. 



Inland of the tots at Weston the soil is very sandy 

 and poor for a distance of some fields ; but inland 

 of this again, the soil improves as the underlying 

 alluvium gets freer from sand. 



The gradual growth of bent, seawards, furnishes the 

 barrier against which the sand is blown, and it is to 

 this grass that we are indebted for safety against 

 inundation of the low-level alluvium that occupies 

 large areas in the county between parallel mountain 

 limestone ridges. 



In the formation of the tots shorewards we have a 

 double sifting process, a sifting of the waves in the 

 formation of the sandy beach, and a sifting of the 



