I live within walking distance of Del Monte beach in Crow City, USA (Also known as Monterey, California).
I enjoy scouring the beach for interesting-looking stones, seashells, and bits of seaworn colored glass fragments.
It seems to me that "my" beach is more fruitful than other beaches / your typical, run-of-the-mill beach. Every time I go, it's different, depending on the wave action from the previous night, but there are usually at least a couple of good "rock fields" as I call them through which to sift for sightly souvenirs.
On some occasions there are several sand dollars, but usually none; one some occasions, there are several beaches dead animals (birds, seals) but usually none; sometimes quite a bit of "sea glass" but usually very little if any. Oftentimes there are a lot of pieces of "holey" rocks (light in weight, either light or dark grey rocks with perforations in them, but their relative abundance differs from visit to visit.
I believe Monterey Bay is quite deep and that the dropoff is pretty dramatic - does this have anything to do with the generosity of the Pacific in this particular spot? It seems that the opposite would take place - since the material to be deposited comes from quite a depth (assumedly) it would take a lot to belch it forth.
Does the variability of material depend on which spot, or which depth of the ocean floor is being scoured with a particular storm / series of waves?
Note: after an unusually heavy amount of erosion of sand (when the sea "takes more than it gives" such as Saturday night, which I noticed Sunday morning) there are also more "treasure hunters" (cats with geiger counters) out on the beach. What are they seeking - lost rings and such, which are closer to the surface after the waves strip away some of the topsand?