The Selection Pressures 3 is a priority contract for the NuCaloric faction in Marathon, and it involves sending certain items back using the DCON on the Dire Marsh map.
There are two tasks to complete, and you’ll need to find inert samples and Organic Data Matrix from specific locations. Let’s look at how to finish both tasks.
Table of contents
Marathon Selection Pressures 3 contract walkthrough
The Selection Pressures 3 contract can be broken down into two parts.
- Deliver inert samples from across Marsh to DCON
- Deliver Organic Data Matrix from Greenhouse to DCON
How to deliver inert samples from across Marsh to DCON
To find the inert samples, you have to go to the West Gate POI. While the official task description says Marsh, you won’t find a place with this name. However, I have marked the exact spots where you’ll find all three Contagion Samples (inert samples).

The first truck is close to the West Gate building (marked as 1). The second one is at the Intersection POI, standing by a barrier. The final one is at the entrance to the Greenhouse POI. If you move from spot 1, you’ll find the two remaining ones in front of you.

All three trucks will be open for you to go inside and get the Contagion Samples. Once you find all three, you can proceed to complete the second task.
How to deliver Organic Data Matrix from Greenhouse to DCON

To find the Organic Data Matrix, head to the marked spot on the location above. You’ll find a small building (part of the main structure). Head inside the room, and collect the Data Matrix.

Once done, you’ll have to find a DCON to send back all the items you found across both tasks. You can find a DCON near the Greenhouse POI, but there are two more present on the map.

The image above has all the DCON spots on Dire Marsh. Interact with one and place the materials in its inventory. Then, wait a few seconds, and you’ll finish the Selection Pressures 3 contract.