[ S3* ] 
I thought, Sir, that this Account might be agree- 
able to you, and to th z Royal Society in general.” 
In my little Excurfions in Queft of Foffils in this 
County, I found, the 13th Inftant, what Naturalifts 
call Lac Luna* but think Dr. Plot is miftaken, 
when he gives it as a Criterion or Sign of good 
Lime- Stone ; for the two Quarries where I found it 
were building Stone, but will not burn into Lime. 
This Matter or Earth makes a ftrong Ebullition with 
Vinegar and Spirit of Vitriol. Some of it was as 
foft as Cream-Cheefe, when I took it out of the 
Fiflure of the Rock } the other was hard, Tome in 
thin Crufts, and fome in pretty thick Lumps. It never 
was taken notice of in this Kingdom before. I alfo 
found, about fix Weeks ago, white native Vitriol, 
which I take to be the Capillaris Sort 5 but as we 
have no Naturalift here, nor Collection of Foffils, 
or any other natural Curiofities (tho’ in great Plenty 
in this Kingdom), it is hard for me to give Names to 
fuch as I have (about 800 Articles) or do difcover 
daily. 
Dublin, Sept. 17, 
1745. 
SIR, 
Tour moft humble , and 
mojl obedient Servant , 
James Simon, 
