Well now, it would take a very long time for the cats to create something as massive as the William Rivers Pitt.
Remember, it took tens of thousands of pigs 75 years to create the miniature Jungfrau here.
Actually, the gardens are so vast no one even notices how they're fertilized.
Searching the inter net for a company that sells these disposers for dog and cat manure. I will have to go back and look under worm farming as this may be where I found it.
Seems one can order a set up that is to be buried in the ground for the disposal and with the order one gets a box of special worms that turn the offal into garden soil. Like composting using only plant material and night crawlers.
I have been told [true or not?] that the pot growers use a waterdown form of Pig offal never straight from the hog to grow their crops in corn fields. Something about the offal from a carnivore is way too strong to be used in its original state---Like a dog that pees in one area will kill the grass. Is this the Ammonia in the offal that does this???
In Panama and some parts of the back woods in the USA people plant their gardens over the septic tank or leach field, Seems to work out well for the farmers that plant their crops, as for those that do not live in the area that 5 pound tomato you bought will give you 3-4 days of the trots.