^4 baker's north YORKSHIRE. 



by the limestone, the former in Kirkdale, the latter near Kirby- 

 moorside, and of springs where a large volume of water flows 

 out from the limestone we have instances at the Keld heads 

 near Pickering, where the Costa has its source, and in the 

 springs of invariable temperature respecting which we shall 

 speak in the chapter on Climate. 



In the main dales of the west, especially in the upper parts of 

 Swaledale and Wensleydale, it will be remembered that the hill 

 slopes are composed of the Yoredale series of strata, and that 

 this consists of six parallel bands of limestone with thick inter- 

 polations of eugeogenous rock. ' Where it exists complete,' 

 writes Professor Phillips, ' as at the head of Wensleydale, the 

 Yoredale series admits of being exactly characterised in a 

 drawing, so that its parts may be again recognised in other situa- 

 tions. For example, take the profile of a mountain whose top 

 is capped with Millstone Grit and whose base rests upon the 

 Lower Scar Limestone, its whole slope being formed of Yore- 

 dale rocks 800 to 1000 feet thick and the series complete. The 

 profile will present the following leading features. At the top 

 of the series, under a round or angular top of Millstone Grit 

 and perhaps a small edge of Chert or Little Limestone the Main 

 or Twelve-fathom Limestone will project into a bold perpen- 

 dicular scar : below it will be a little concave or flat slope 

 terminated by a second and less conspicuous projection of the 

 thinner Underset Limestone : a long slope succeeds, simple or 

 slightly varied with rising undulati.ons corresponding to the hard 

 gritstones interstratified with shales : this ends above a single or 

 double scar of the Middle Limestone, which is very conspicuous 

 where thick, as in Addlebrough and Penhill, but easily lost by 

 the detritus of the superior rocks where it is thin, as above 

 Hawes : below this there is another slope to the Simonside 

 Limestone, which forms a smooth terrace ; another steep slope to 

 the Hardraw Limestone, which runs for miles along both sides 

 of Wensleydale in a remarkable terrace, occasionally wooded, 

 always very abrupt and rocky at the edge, and based upon a 



