78 REPORT — 1839. 



part of their cargo before they could come up to Liverpool, which at 

 that time was inferior to Chester in importance. The entrance has 

 since become deeper, and a channel called "Helbre Swash" has been 

 formed across the " Hyle sand," which in 1687 was dry at high water 

 of the neap tides. Many similar changes are shown to have taken 

 place, but the most important is one which is now in progress by hu- 

 man agency. This is a new channel, about one third of a mile wide 

 and thi'ee quarters of a mile long, which has already been deepened 

 upwards of four feet, and will shortly be thrown open to shipping 

 under the name of the Victoria channel. The deepening is eifected by 

 dragging a large iron harrow, invented by Lieut. Lord, over the sand- 

 bank by means of a steam- vessel. This process is continued daily dur- 

 ing the ebb tide, and the sand and mud thus loosened from the bottom 

 is carried out to sea by the current. The complete success of this 

 invention recommends it to the notice of persons connected with other 

 harbours. 



On Peat Bogs. By G. H. Adams, M.D, 



Prof. Shepard, of Yale College, exhibited a collection of organic 

 remains from the limestones of North America, numbered ; many of 

 the specimens corresponding to the numbers towards one end of the 

 series, belonging certainly to species described in Mr. Murchison's 

 work on the Silurian System ; many of those toward the other end 

 as certainly identical with species figured by Professor Phillips in his 

 work on the Geology of Yorkshire. 



ZOOLOGY AND BOTANY. 



On the Formation of Woody Tissue. By Mr. Edwin Lankester. 



The tissues of plants, for the sake of convenience, are divided into 

 five, the origin of which may be all traced to the simple cell. How 

 they are formed, is an undecided qviestion, more especially with re- 

 gard to woody tissue. Du Petit Thouars supposes that woody fibre 

 is formed by the buds and leaves, and sent down by them between the 

 bark and wood, where they are nourished by the cambium. Others 

 suppose that it is formed from the wood or bark. The most promi- 

 nent features of woody tissue are its length, and hardness from the 

 deposit of secretions in its interior. These points, however, do not 

 constitute an essential difference between woody and cellular tissue, 

 as we find the latter lengthened in the form now called Pitted tissue, 

 or Vasiform tissue, and hardened d^s, in the endocarps oi Amygdalece, &c. 



If in the term woody tissue all lengthened, hardened tissue be in- 



