I had a note "John Thompson's Atlas of Scotland 1832 who used the 1782 map, but made a few changes".

Ainslie's 1782 map is at :
http://maps.nls.uk/counties/view/?id=685

Thompson's 1832 map is at :
http://www.nls.uk/maps/early/540.html

Balterson (if this is the one you want) is just above Clary, south Penningham Parish, shown on previous attachments.

To find it go to one of the above maps, and click on the area just north of Wigton Bay and click again (or double click) to keep zooming in.