HARDWICKE'S SCIENCE-GOSSIP. 



Fig-. 2. Daylight Aurora. 



rays that appear as lights in llic niglit-time are less 

 intense than sunlight ; consequently, during day- 

 light they generally will appear as dark instead of 

 hright streaks, and may easily be mistaken for a 

 distant shower or light fleecy cloud. Of the latter 

 I am now quite positive, as very frequently on a 

 bright frosty morning I have been surprised to see 

 what then was supposed by me to be a distant 

 shower, but now is known to have been a morning 

 aurora. G. H. Kinahan. 



THE STORY OF A GRAVEL-PIT. 

 By J. E. Taylor, P.G.S., etc. 



I AM the last of my race. My brother story- 

 tellers have had their day, and ceased to be. 

 Had you questioned me a few years ago, I should 

 have been like Canning's Knife grinder, and had 

 nothing to tell. Even now my story is not complete. 

 New editions are constantly coming out, although 

 tlicir general truth remains unaltered. 



Who among my listeners has not played, when a 

 child, in a sand- or gravel-pit ? You have them in 

 abundance, scattered over the surface of the country. 

 But there are gravel-pits and gravel-pits — a differ- 

 ence without a popular distinction. 



Those I particularly represent are always situated 

 on the banks of some river- valley. Hence their other 

 geological names of " Valley-gravels " and " River- 

 gravels." Frequently they form terraces flanking 

 the present course of the rivers, and you may iden- 

 tify two of these terraces,— a low-lying one and a 

 higher. If you could strip off these banks of gravel, 

 you would find the bare rock beneath, or else some 

 thick slieet of boulder clay, which had been scooped 



out to make the present river-valley. Banked up 

 against these old denuded surfaces are the gravels, 

 whose excavations are so well known as pits. I am 

 one of them, and I propose to tell you my story, as 

 well as I can recollect it. Although I can hardly 

 define the difference between the gravels to which 

 I belong and those which belong to the Glacial 

 series, generally the Middle Drift, yet the practised 

 ej'e readily learns to detect that there is a difference. 

 The pebbles composing our beds are well rounded, 

 showing they have undergone a tremendous deal of 

 wear-and-tear. They are composed of different 

 kinds of rock, just as you would expect when j'ou 

 know they have been washed out 'of the boulder 

 clays, or brought down by the river in its passage 

 over the outcrops of successive beds. The flint 

 pebbles have generally an oily look about them, and 

 all the pebbles are red and ochreous. Their position 

 along the river-valley, however, is always the best 

 test. Some of these valley-gravels are very thick, 

 whilst others extend as mere banks of local distri- 

 bution. All of them, however, indicate some degree 

 of antiquity, inasmuch as you will find ancient trees 

 growing on the most recent of these teiTaces, and, 

 here and there, old ruins which stand upon them. 

 In fact, the gravel-pits indicate a gradual rise in 

 the land for them to occupy their present heights 

 above the river-level. The gravels were originally 

 brought down by the ancestor of the present river> 

 when it was broader and perhaps more turbulent, 

 at the close of the Glacial epoch, when the climaturc 

 was more severe than it now is, and the quantity of 

 rain and snow which annually fell much greater, so 

 that the river-valley was subjected to great floods, 

 which brought down the materials of which we are 

 composed. 



