Stinting for Diatoms. 197 



collect some of tlie weeds from the sides of the boggy pool, 

 for in such localities we may expect to find some of the rarer 

 alpine forms, Navicula rhomboides, obtusa, Pinnidaria divergens, 

 lata, and Alpina, for instance. The pale green flocculent mass 

 growing in quantities like a conferva, is well worth collecting, 

 for it is a pure gathering of Tabellaria fiocculosa and fenestrata. 



In tramping over this quaking bog it is well to roll up a 

 bundle of the Sphagnum, for on afterwards squeezing out the 

 water, we may be rewarded by finding some of the rarer species 

 of Pinnularia, such as PLemiptera and Alpina. 



Before leaving this rocky part of the country for the flat 

 country below, let us scrape some of the brown mucus from the 

 face of the dripping rocks, for it will probably yield such forms 

 as Epithemia, Gocconeis Tliwaitsii, Navicula Trinodis, Denticida 

 sinuata, etc. 



The weather being warm we will quench our thirst at the 

 little spring in the cavern-like hollow in the rocky roadside. 

 Observe, the roof of the little cavern is quite covered with a 

 chocolate-brown mass, which feels rough and gritty to the fin- 

 gers. Here is a splendid and pure gathering of Orthosira. 

 arenaria, and I recommend you to take a good store of it 

 away with you, for it is seldom one finds this fine form so pure 

 and unmixed. 



Proceeding towards the low country let us take a scrape 

 from the side of this horse-trough, for it is quite brown. It is 

 well we have done so, for it is a nice pure gathering of Cyclo- 

 tella operculata and Pinnularia pygmoea. 



Passing a little further on we come to a clump of ash trees, 

 with a crop of moss growing on their trunks. Perhaps you 

 may smile when I proceed to peel off this moss and store it 

 away in a bundle in my satchel. On washing the moss after- 

 wards, however, I may be rewarded with some of our most 

 local and rare species, viz. Orthosira mirabilis, mixed with 

 Navicida tumida, Pinnularia borealis, and Orthosira spinosa. 



Having secured a bundle of moss from the tree trunks,* we 

 will take another from the roof of this old thatched cottage, 

 the north side of which is quite carpeted with beautiful green 

 moss. This will probably yield Nitzschia Amphioxys and Pin- 

 nularia borealis. 



The white-coloured stratum of earth exposed in the cutting 

 on the roadside must now be examined, for it is probably a 

 deposit of fossil, diatomaceous earth, in which case a large 

 piece must be secured. 



These fossil deposits arts generally composed of a compact 

 mass of Diatomaceas of recent as well as extinct species. The 

 deposit we are at present examining is several feet thick, and 

 has at some remote period formed the bed of a lake, the 



vol. i. — NO. III. p 



