This bromalite gets its name from the Greek hira (gut or intestine), and the Greek bromus (food). It presents as an "elongate(d), convoluted, longitudinally-striated cylinder that tapers on both ends" and comprised of siderite.
Since body fossils (carcasses) are not present or otherwise associated with this type of specimen, there is some debate as to whether these are geological (pseudofossils) or cololites.
Reference: Hunt, A. P., Lucas, S. G. & Spielmann, J. A. (2012b): The bromalite collection at the National Museum of Natural History (Smithsonian Institution) with descriptions of new ichnotaxa and notes on other significant coprolite collections - New Mexico Museum of Natural History and Science, Bulletin, 57: 105-114.
Locally referred to as "pineapple stones," this siderite dubiocoprolite may have originated meat-eating marsupial! This particular example is from a fossiliferous area. However, it is hard to say if inclusion-free siderite extrusions such as this are actually coprolites.
This specimen has clearly defined sphincter marks. This was found in an area approximately 100 miles south of Pico Truncado in an area where dinosaur bone from the Jurassic age is abundant. However, a saltwater clam named trigonia, believed to be from the Cretaceous period, can also be found.