Larry:
If you haven't already found your pebbles. You could try making a "stamp" and pressing is into thin poured layers of plaster. I recently read an article in my newly acquired book ARCHITECTURAL MODELLING in 4mm Scale. It describes making a stamp out of various sizes of tubing brass,styrene etc. short lengths are cut and placed together like cans on a shelf. Vary the size and make as large a section as required. Once all pieces have been bonded together a handle can be attached either by soldering or gluing depending on the medium used to create the stamp.
Once you have it put together you impress the "stamp" into the plaster and it forms the cobbles quickly and easily. To vary the pattern you rotate the stamp as you proceed.
The full title of the book is:
Architectural Modelling in 4mm Scale
- Dave Rowe - 1983 - Wild Swan Publications Ltd.
Hopgoods Farm Cottage, Upper Bucklebury, Berks U.K.
ISBN: 0 906867 12 6
I have learned many new ideas that I will be using in future projects just in several pages I have read so far. If you can find a copy it is worth a look.
Cheers;
Gregory