HYACINTH CULTURE AT HAARLEM 153 



a heap of leaf-manure, a second heap of cow-manure, and a 

 third heap of sand is now made of sand brought from the 

 dunes, or it can be dug out of the very ground beneath to 

 the depth of some feet. Though all the soil about Haarlem 

 and its neighbourhood is mainly sand, especially near the 

 dunes, where most of the bulb fields are, yet they prefer to 

 fetch sand from a distance rather than take any from the 

 surface of their own ground. This sand should be as care- 

 fully examined as is the manure, so that, now that I think of 

 it, I must enter into further details, which will be thought 

 unnecessary by some people, but others will be glad to follow 

 the spirit of our inquiry. 



The nature of the soil in Holland proves that the country 

 has undergone great geological changes, apart from the 

 continual encroachments of the sea. 



It seems that at a very distant period, perhaps before or 

 after the Deluge, the country must have been covered 

 over with forests, as were Germany and Gaul in later 

 times. 



Either in the great Deluge of Sacred Writ, or during one 

 of the partial deluges that men of science speak of (but of 

 which no one seems to have any positive knowledge), these 

 trees must have been thrown down and laid on the ground 

 in the direction of east to west, in such a manner that where 

 they fell they form strata (or layers), which time has reduced 

 to a thickness of six or eight inches at the most. 



It may be that this layer of trees was at first exposed to 

 the air, or (as is more likely) was for some time covered by 

 the sea, which, depositing sand, pressed and consolidated it 

 into the mass which we now see, and which is found in all 

 parts of Holland and Zealand, and is known under the name 

 of Darry or Derry. 



It is very easy to perceive that it is old wood decayed 

 into the earth and reduced to the loose consistency of a sort 



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